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Additional Question - Chapter 5 - Coordination Chemistry - 12th Chemistry Guide Samacheer Kalvi Solutions

Updated On 11-02-2025 By Lithanya


Additional Question
1 Mark Questions and Answers
I. Choose the correct answer.
Question 1.

Which one of the following is an example of coordination compound?
(a) Common salt
(b) Mohr's salt
(c) Haemoglobin
(d) Potash alum
Answer:
(c) Haemoglobin
Question 2.
Which one of the following is not an example of complex salt?
(a) Haemoglobin
(b) Chlorophyll
(c) Cobalamine
(d) Ferrous ammonium sulphate
Answer:
(d) Ferrous ammonium sulphate
Question 3.
Which one of the complex salt is acting as a photo sensitiser in photosynthesis process?
(a) Wilkinson's compound
(b) Cobalamine
(c) Chlorophyll
(d) Haemoglobin
Answer:
(c) Chlorophyll
Question 4.
The complex compound act as oxygen transporter of human is
(a) Haemoglobin
(b) Chlorophyll
(c) Cyano cobalamine
(d) Wilkinson compound
Answer:
(a) Haemoglobin

5. Which metal is present in vitamin $B_{12}$ ?
(a) Iron
(b) Cobalt
(c) Manganese
(d) Copper
Answer:
(b) Cobalt
Question 6.
Which one of the following metal ion is present in Haemoglobin?
(a) $\mathrm{Fe}^{2+}$
(b) $\mathrm{CO}^{3+}$
(c) $\mathrm{Mn}^{2+}$
(d) $\mathrm{Cu}^{2+}$
Answer:
(a) $\mathrm{Fe}^{2+}$
Question 7.
Consider the following statements
(i) Mohr's salt answers the presence of $\mathrm{Fe}^{2+}, \mathrm{NH}^{4+}$ and $\mathrm{SO}_4{ }^{2-}$ ions.
(ii) Potassium Ferri thio cyanate answers the presence of $\mathrm{K}^{+}, \mathrm{Fe}^{3+}, \mathrm{SCN}$ ions
(iii) In coordination compound, the complex ion does not loose its identity and never dissociate to give simple ions.
Which of the above statements is/are correct?
(a) (ii) only
(b) (i) and (iii)
(c) (ii) and (iii)
(d) (iii) only
Answer:
(b) (i) and (iii)
Question 8.
How many moles of $\mathrm{AgCl}$ are precipitated on the reaction of one mole of $\mathrm{COCl}_3 \cdot 5 \mathrm{NH}_3$ with $\mathrm{AgNO}_3$ ?
(a) 3
(b) 1
(c) 2
(d) 5
Answer:
(c) 2

Question 9.
What are primary and secondary valency of cobalt in $\mathrm{COCl}_3 \cdot 6 \mathrm{NH}_3$ ?
(a) 3,3
(b) 6,3
(c) 3,6
(d) 6,6
Answer:
(c) 3,6
Question 10.
Consider the following statements.
(i) The outer sphere in coordination compound is called ionisation sphere.
(ii) The primary valences are non directional while secondary valences are directional.
(iii) The primary valances of a metal ion is negative and it is satisfied by positive ions.
Which of the above statements is/are not correct?.
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (iii) only
(d) (ii) only
Answer:
(c) (iii) only
Question 11.
Which one of the following is the coordination entity in $\mathrm{k}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right]$ ?
(a) $4 \mathrm{~K}^{+}$
(b) $\left[\mathrm{Fe}(\mathrm{CN})_6\right]^4$
(c) $\mathrm{Fe}^{2+}$
(d) $\mathrm{CN}^{-}$
Answer:
(b) $\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{4-}$
Question 12.
Which of the following is called Lewis acid in $\left[\mathrm{Ni}(\mathrm{CO})_4\right]$ ?
(a) $\mathrm{Ni}^{2+}$
(b) $\mathrm{CO}$
(c) $\mathrm{Ni}^{4+}$
(d) $\mathrm{CO}$
Ans.wer:
(a) $\mathrm{Ni}^{2+}$

Question 13.
Identify the lewis acid in $\mathrm{K}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right]$ ?
(a) $\mathrm{Fe}^{3+}$
(b) $\mathrm{Fe}^{2+}$
(c) $\mathrm{K}^{+}$
(d) $\mathrm{CN}^{-}$
Answer:
(b) $\mathrm{Fe}^{2+}$
Question 14.
The coordination polyhedra of $\mathrm{K}_3\left[\mathrm{Fe}(\mathrm{CN})_6\right]$ is
(a) Square planar
(b) Tetrahedral
(c) Linear
(d) Octahedral
Answer:
(d) Octahedral
Question 15.
The coordination polyhedra of $\left[\mathrm{Ni}(\mathrm{CO})_4\right]$ is
(a) Octahedral
(b) Tetrahedral
(c) Square planar
(d) Pyramidal
Answer:
(b) Tetrahedral
Question 16.
What is the coordination number of $\mathrm{Fe}^{2+}$ in $\mathrm{K}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right]$ ?
(a) 4
(b) 6
(c) 3
(d) 2
Answer:
(b) 6

Question 17.
Identify the coordination number of $\mathrm{Ni}^{2+}$ in $\left[\mathrm{Ni}(\mathrm{en})_3\right] \mathrm{Cl}_2$
(a) 3
(b) 2
(c) 6
(d) 5
Answer:
(c) 6
Question 18.
The oxidation state of $\mathrm{Fe}$ in $\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{4-}$ is
(a) II
(b) III
(c) VI
(d) IV
Answer:
(a) II
Question 19.
Identify the oxidation state of cobalt in $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_5 \mathrm{Cl}\right]^{2+}$ ?
(a) +2
(b) +3
(c) +4
(d) +5
Answer:
(b) +3
Question 20.
What is the coordination number of $\mathrm{Pt}$ in $\left[\mathrm{Pt}\left(\mathrm{NO}_2\right)\left(\mathrm{H}_2 \mathrm{O}\right)\left(\mathrm{NH}_3\right)_2\right] \mathrm{Br}$ ?
(a) 3
(b) 4
(c) 2
(d) 5
Answer:
(b) 4
Question 21.
Which one of the following is an example of cationic complex?
(a) $\mathrm{Na}\left[\mathrm{Ag}(\mathrm{CN})_2\right]$
(b) $\left[\mathrm{Ag}\left(\mathrm{NH}_3\right)_2\right] \mathrm{Cl}$
(c) $\left[\mathrm{Ni}(\mathrm{CO})_4\right]$
(d) $\mathrm{K}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right]$
Answer:
(b) $\left[\mathrm{Ag}\left(\mathrm{NH}_3\right)_2\right] \mathrm{Cl}$

Question 22.
Which of the following is an example of anionic complex?
(a) $\left[\mathrm{Ag}\left(\mathrm{NH}_3\right)_2\right] \mathrm{Cl}$
(b) $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_6\right] \mathrm{Cl}_3$
(c) $\left[\mathrm{Fe}(\mathrm{CO})_5\right]$
(d) $\mathrm{K}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right]$
Answer:
(d) $\mathrm{K}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right]$
Question 23.
Which one of the following is a neutral complex?
(a) $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_3\left(\mathrm{Cl}_3\right)\right]$
(b) $\left[\mathrm{Ag}\left(\mathrm{NH}_3\right)_2\right]^{+}$
(c) $\mathrm{K}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right]$
(d) $\mathrm{Na}\left[\mathrm{Ag}(\mathrm{CN})_2\right]$
Answer:
(a) $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_3\left(\mathrm{Cl}_3\right)\right]$
Question 24.
Which one of the following is a homoleptic complex?
(a) $\left.\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_3\right]\left(\mathrm{Cl}_3\right)\right]$
(b) $\left[\mathrm{Pt}\left(\mathrm{NH}_3\right)_2 \mathrm{Cl}_2\right]$
(c) $\left[\mathrm{Pt}\left(\mathrm{NO}_2\right)\left(\mathrm{H}_2 \mathrm{O}\right)\left(\mathrm{NH}_3\right)_2\right] \mathrm{Br}$
(d) $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right] \mathrm{Cl}_3$
Answer:
(d) $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right] \mathrm{Cl}_3$
Question 25.
Which one of the following is a heteroleptic complex?
(a) $\left[\mathrm{Pt}\left(\mathrm{NO}_2\right)\left(\mathrm{H}_2 \mathrm{O}\right)\left(\mathrm{NH}_3\right)_2\right] \mathrm{Br}$
(b) $\left[\mathrm{Ni}(\mathrm{CO})_4\right]$
(c) $\left[\mathrm{Cb}\left(\mathrm{NH}_3\right)_6\right] \mathrm{Cl}_3$
(d) $\mathrm{K}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right]$
Answer:
(a) $\left[\mathrm{Pt}\left(\mathrm{NO}_2\right)\left(\mathrm{H}_2 \mathrm{O}\right)\left(\mathrm{NH}_3\right)_2\right] \mathrm{Br}$

Question 26.
Which one of the following is called as Zeise's salt?
(a) $\left[\mathrm{Pt}\left(\mathrm{NH}_3\right)_4\right]\left[\mathrm{Pt} \mathrm{Cl}_4\right]$
(b) $\mathrm{K}\left[\mathrm{PtCl}_3\left(\mathrm{C}_2 \mathrm{H}_4\right)\right]$
(c) $\mathrm{K}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right]$
(d) $\left[\mathrm{Fe}(\mathrm{CO})_5\right]$
Answer:
(b) $\mathrm{K}\left[\mathrm{PtCl}_3\left(\mathrm{C}_2 \mathrm{H}_4\right)\right]$
Question 27.
$\left[\mathrm{Pt}\left(\mathrm{NH}_3\right)_4\right]\left[\mathrm{Pt} \mathrm{Cl}_4\right]$ is called as
(a) Zeigler Natta Catalyst
(b) Zeises' salt
(c) Magnus's green salt
(d) Mohr's salt
Answer:
(c) Magnus's green salt
Question 28.
The IUPAC name of $\mathrm{K}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right]$ is
(a) Potassium hexacyanido Ferrate (III)
(b) Potassium hexacyanidoferrate (II)
(c) Potassium ferrocyanide
(d) Potassium ferricyanide
Answer:
(b) Potassium hexa cyanido Ferrate (II)
Question 29.
Which of the following is the IUPAC name of $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_6\right] \mathrm{Cl}_3$ ?
(a) Hexamminecobalt (III) chloride
(b) Hexammine cobalt (II) chloride
(c) Hexamminechloro cobaltate(III)
(d) Trichlorohexammine cobalt (III)
Answer:
(a) Hexamminecobalt (III) chloride

Question 30.
The IUPAC name of $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_4 \mathrm{Cl}_2\right] \mathrm{Cl}$ is
(a) Tetrammine dichlorido cobalt (III) chloride
(b) Dichlorido tetrammine cobalt (III) chloride
(c) Tetrammine cobalt (III) trichloride
(d) Tetrammine dichlorido cobaltate (III)
Answer:
(a) Tetramminedichloridocobalt (III) chloride
Question 31.
Which one of the following is the IUPAC name of $\left[\mathrm{Cr}(\mathrm{en})_3\right]\left[\mathrm{CrF}_6\right]$
(a) Triethylamine chromium (III) hexa fluriod chromium (III).
(b) Tris (ethane -1, 2 - diamine) chromium (III) hexa flurido chromate (III)
(c) Hexa fluoro chromium (III) tris (ethane - 1, 2 - diamined) chromium (III)
(d) Hexa fluoro chromate (III) triethyl amine chromium (III)
Answer:
(b) Tris (ethane - 1,2 - diamine) chromium (III) hexa fluorido chromate (III)
Question 32.
The IUPAC name of $\mathrm{Na} 2[\mathrm{Ni}(\mathrm{EDTA})]$ is
(a) Disodium tetra acetato nickalate (II)
(b) Sodium 2, 2', 2", 2"t - (ethane 1,2 - diyldinitrilo) tetra acetato nickelate (II)
(c) Ethylene tetra acetato nickalate (II)
(d) Sodium tetraacetato nickel (II)
Answer:
(b) Sodium 2, 2, 2", 2" - (ethane - 1, 2-diyldinitrilo) tetra acetato nickelate (II)

Question 33.
The formula of Hexafluorido ferrate (II) ion is
(a) $\left[\mathrm{FeF}_6\right]^{4-}$
(b) $\left[\mathrm{Fe} \mathrm{F}_6\right]^{3-}$
(c) $\left[\mathrm{FeF}_6\right]^{2-}$
(d) $\left[\mathrm{FeF}_6\right]^{3+}$
Answer:
(a) $\left[\mathrm{Fe} \mathrm{F}_6\right]^{4-}$
Question 34.
What is the IUPAC name of $\left[\mathrm{CO}\left(\mathrm{CO}_3\right)\left(\mathrm{NH}_3\right)_4\right] \mathrm{Cl}$ ?
(a) Carbonato tetraammine cobalt (III) chloride
(b) Tetraamminecarbanatocobalt(III) chloride
(c) Carbonato tetra ammonium cobaltate (HI).
(d) Carbonato tetraammine cobaltate (II)
Answer:
(b) Tetraamminecarbanatocobalt(III) chloride
Question 35.
What is the formula of Diaquadiiododinitrito $-\mathrm{k} \mathrm{O}$ palladium (IV)?
(a) $\left[\mathrm{Pd}_2(\mathrm{ONO})_2\left(\mathrm{H}_2 \mathrm{O}\right)_2\right]$
(b) $\left[\mathrm{Pd} \mathrm{I}_2\left(\mathrm{NO}_2\right)_2\left(\mathrm{H}_2 \mathrm{O}\right)_2\right]$
(c) $\left[\mathrm{PdI}_2\left(\mathrm{NO}_3\right)_2 \mathrm{H}_2 \mathrm{O}\right]$
(d) $\left[\mathrm{Pd} \mathrm{I}_2\left(\mathrm{NO}_3\right)\left(\mathrm{H}_2 \mathrm{O}\right)\right]$
Answer:
(a) $\left[\mathrm{Pd} \mathrm{I}_2(\mathrm{ONO})_2\left(\mathrm{H}_2 \mathrm{O}\right)_2\right]$
Question 36.
What is the formula of Triammine triaquachromium (III )chloride?
(a) $\left[\mathrm{Cr} \mathrm{Cl}_3\right]\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_3\right] \mathrm{Cl}_3$
(b) $\left[\mathrm{Cr}\left(\mathrm{NH}_3\right)_3\left(\mathrm{H}_2 \mathrm{O}\right)_3\right] \mathrm{Cl}_3$
(c) $\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]\left[\mathrm{CrCl}_3\right]$
(d) $\left[\mathrm{Cr}\left(\mathrm{NH}_3\right)_2\left(\mathrm{H}_2 \mathrm{O}\right)_4\right] \mathrm{Cl}_3$
Answer:
(b) $\left[\mathrm{Cr}\left(\mathrm{NH}_3\right)_3\left(\mathrm{H}_2 \mathrm{O}\right)_3\right] \mathrm{Cl}_3$

Question 37.
Which type of isomerism is possible in $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_5\left(\mathrm{NO}_2\right)\right]^{2+}$ ?
(a) Ligand isomerism
(b) Coordination isomerism
(c) Ionisation isomerism
(d) Linkage isomerism
Answer:
(d) Linkage isomerism
Question 38.
[ $\left.\mathrm{Cr}\left(\mathrm{NH}_3\right)_4 \mathrm{Cl} \mathrm{Br}\right] \mathrm{NO}$, and $\left[\mathrm{Cr}\left(\mathrm{NH}_3\right)_4 \mathrm{ClNO}_2\right] \mathrm{Br}$ are examples of
(a) Linkage isomerism
(b) Ionisation isomerism
(c) Coordination isomerism
(d) Hydrate isomerism
Answer:
(b) Ionisation isomerism
Question 39.
The type of isomerism present in $\left[\mathrm{Pt}\left(\mathrm{NH}_3\right)_4\right]\left[\mathrm{Pd}(\mathrm{Cl})_4\right]$ and $\left[\mathrm{Pd}\left(\mathrm{NH}_3\right)_4\right]\left[\mathrm{Pt}(\mathrm{Cl})_4\right]$ is
(a) Solvate isomerism
(b) Ionisation isomerism
(c) Coordination isomerism
(d) Linkage isomerism
Answer:
(c) Coordination isomerism
Question 40.
Isomerism present in $\mathrm{CrCl}_3 6 \mathrm{H}_2 \mathrm{O}$ is
(a) Solvate isomerism
(b) Ligand isomerism
(c) Linkage isomerism
(d) Ionisation isomerism
Answer:
(a) Solvate isomerism
Question 41.
Geometrical isomerism is exhibited by
(a) Tetrahedral complex
(b) Linear complex
(c) Square planar complex
(d) All the above

Answer:
(c) Square planar complex
Question 42.
The type of isomerism possessed by $\left[\mathrm{CO}(\mathrm{en})_3\right]^{3+}{ }_{\text {is }}$
(a) Cis-trans isomerism
(b) Optical isomerism
(c) Ionisation isomerism
(d) Linkage isomerism
Answer:
(A) Optical isomerism
Question 43.
VB theory was proposed by
(a) Alfred Werner
(b) Bethe and Van vleck
(c) Linus Pauling
(d) Louis de Broglie
Answer:
(c) Linus Pauling
Question 44.
Bethe and Van vleck proposed a coordination theory named as
(a) Werner's theory
(b) Valence bond theory
(c) Molecular orbital theory
(d) Crystal field theory
Answer:
(d) Crystal field theory
Question 45.
Which one of the following geometry is possessed by $\left[\mathrm{Cu} \mathrm{Cl}_2\right]^{-}$and $\left[\mathrm{Ag}(\mathrm{CN})_2\right]$ ?
(a) Trigonal planar
(b) Linear
(c) Tetrahedral
(d) Square planar
Answer:
(b) Linear

Question 46.
The type of hybridisation take place in $\left[\mathrm{HgI}_3\right]^{-}$is
(a) $\mathrm{sp}$
(b) $\mathrm{sp}^3$
(c) $\mathrm{sp}^2$
(d) $\mathrm{dsp}^2$
Answer:
(c) $\mathrm{sp}^2$
Question 47.
Square planar complexes have type of hybridisation
(a) $\mathrm{sp}^3$
(b) $\mathrm{dsp}^2$
(c) $\mathrm{sp}^3 \mathrm{~d}$
(d) $\mathrm{sp}^3 \mathrm{~d}^2$
Answer:
(b) $\mathrm{dsp}^2$
Question 48.
Which type of hybridisation take place in $\left[\mathrm{Fe}(\mathrm{CO})_5\right]$ ?
(a) $\mathrm{dsp}^2$
(b) $\mathrm{d}^2 \mathrm{sp}^3$
(c) $\mathrm{sp}^3 \mathrm{~d}^2$
(d) $\mathrm{dsp}^3$
Answer:
(d) $\mathrm{dsp}^3$
Question 49.
The $\mathrm{d}$ orbital involved in $\mathrm{dSP}^3$ hybridisation of $\left[\mathrm{Fe}(\mathrm{CO})^5\right]$ is
(a) dxy
(b) dyz
(c) $d x z$
(d) $d x^2 y^2$
Answer:
(d) $d x^2 y^2$
Question 50.
In octahedral geometry, the type of hybridisation involved is
(a) $\mathrm{sp}^3 \mathrm{~d}^2$
(b) $\mathrm{d}^2 \mathrm{sp}^3$
(c) $\mathrm{dsp}^3$
(d) a or b

Answer:
(d) a or b
Question 51.
The $\mathrm{d}$ orbitals involved in $\mathrm{d}^2 \mathrm{sp}^3$ hybridization are
(a) $d_{x y}, d_{y z}$
(b) $d_{x^2}-y^2, d_z$
(C) $d_{z y}, d_{x z}$
(d) $d_{x y}, d_{y z}$
Answer:
(b) $\mathrm{d}_{\mathrm{x}}{ }^2-\mathrm{y}^2, \mathrm{~d}_{\mathrm{z}}$
Question 52.
Which type of hybridisation is possible in $\left[\mathrm{Ni}(\mathrm{CN})_4\right]^{2-}$ and $\left[\mathrm{Pt}\left(\mathrm{NH}_3\right)_4\right]^{2+}$ ?
(a) $\mathrm{dsp}^2$
(b) $\mathrm{dsp}^3$
(c) $\mathrm{sp}^3 \mathrm{~d}$
(d) $\mathrm{sp}^3 \mathrm{~d}^2$
Answer:
(a) $\mathrm{dsp}^2$
Question 53.
The geometry possible in $\left[\mathrm{Fe} \mathrm{F}_6\right]^{4-}$ and $\left[\mathrm{CoF}_6\right]^{4-}$ is
(a) Trigonal bipyramidal
(b) Square planar
(c) Octahedral
(d) Tetrahedral
Answer:
(c) Octahedral
Question 54.
The geometry of $\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{3-}$ is
(a) Tetrahedral
(b) Octahedral
(c) Square planar
(d) Trigonamal bipyramidal
Answer:
(b) Octahedral
Question 55.
Which one of the following complex is paramagnetic in nature?
(d) $\left[\mathrm{Ni}(\mathrm{CN})_4\right]^{4-}$
(b) $\left[\mathrm{Ni}(\mathrm{CO})_4\right]$
(c) $\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{3-}$

Answer:
(c) $\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{3-}$
Question 56.
Which one of the following complex has magnetic moment as $4.899 \mathrm{BM}$ ?
(a) $\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{3-}$
(b) $\left[\mathrm{Ni}(\mathrm{CN})_4\right]^{4-}$
(C) $\left[\mathrm{COF}_6\right]^{3-}$
(d) $\left[\mathrm{Ni}(\mathrm{CO})_4\right]$
Answer:
(c) $\left[\mathrm{COF}_6\right]^{3-}$
Question 57.
Consider the following statements,.
(i) VB theory does not explain the colour of the complex
(ii) VB theory does not explain the magnetic properties
(iii) VB theory does not provide a quantitative explanation about inner orbital complexes.
Which of the above statements is/are not correct?
(a) (i) only
(b) (i) and (ii)
(c) (iii) only
(d) (ii) only
Answer:
(c) (iii) only
Question 58.
Consider the following statements,.
(i) Complexes of central metal atom such as of $\mathrm{Cu}^{+}, \mathrm{Zn}^{2+}$ are coloured
(ii) Most of the transition metal complexes are colourless
(iii) Negative CFSE value indicates that low spin complex is favoured
Which of the above statements is/are correct?
(a) (i) and (ii)
(b) (iii) only
(c) (ii) only
(d) (i), (ii) only (iii)
Answer:
(b) (iii) only

Question 59.
Which is used for the separation of lanthanides, in softening of hard water and also in removing lead poisoning?
(a) $\left[\mathrm{Ni}(\mathrm{CO})_4\right]$
(b) EDTA
(c) $\left[\mathrm{Ni}(\mathrm{DMG})_2\right]$
(d) $\mathrm{Ti} \mathrm{Cl}_4+\mathrm{AI}\left(\mathrm{C}_2 \mathrm{H}_5\right)_3$
Ans.
(b) EDTA
Question 60 .
Which complex is used as an antitumor drug in cancer treatment?
(a) $\mathrm{Ca}$ - EDTA chelate
(b) EDTA
(c) $\mathrm{Ti} \mathrm{Cl}_4+\mathrm{Al}\left(\mathrm{C}_2 \mathrm{H}_5\right)_3$
(d) Cis - Platin
Answer:
(d) Cis - Platin
Question 61.
What is the name of $\mathrm{Na}_3\left[\mathrm{Ag}\left(\mathrm{S}_2 \mathrm{O}_3\right)_2\right]$
(a) Sodiumargentothiosulphate
(b) Sodium dithio sulphato angentate (I)
(c) $\mathrm{HyPO}$
(d) Sodium thiosulphate
Answer:
(b) Sodiumdithiosulphatoangentate (I)
Question 62 .
Which of the following will give a pair of enantiomorphs?
(a) $\left[\mathrm{Cr}\left(\mathrm{NH}_3\right)_6\left[\mathrm{CO}(\mathrm{CN})_6\right]\right.$
(b) $\left[\mathrm{CO}(\mathrm{en})_2 \mathrm{Cl}_2\right] \mathrm{Cl}$
(c) $\left[\mathrm{Pt}\left(\mathrm{NH}_3\right)_4\left[\mathrm{Pt}(\mathrm{Cl})_6\right]\right.$
(d) $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_4 \mathrm{Cl}_2\right] \mathrm{NO}_2$
Answer:
(b) $\left[\mathrm{CO}(\mathrm{en})_2 \mathrm{Cl}_2\right] \mathrm{Cl}$
Question 63.
In which of the following coordination entitites, the magnitude of $\Delta_0$ (CFSE in octahedral field) will be maximum?
(a) $\left[\mathrm{CO}(\mathrm{CN})_6\right]^{3-}$

(b) $\left[\mathrm{CO}\left(\mathrm{C}_2 \mathrm{O}_4\right)_3\right]^{3-}$
(c) $\left[\mathrm{CO}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{3+}$
(d) $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_6\right]^{3+}$
Answer:
(a) $\left[\mathrm{CO}(\mathrm{CN})_6\right]^{3-}$
Question 64.
Which of the following complex ion is expected to absorb visible light?
(a) $\left[\mathrm{Zn}\left(\mathrm{NH}_3\right)_6\right]^{2+}$
(b) $\left[\mathrm{Sc}\left(\mathrm{H}_2 \mathrm{O}\right)_3\left(\mathrm{NH}_3\right)_3\right]^{3+}$
(c) $\left[\mathrm{Ti}(\mathrm{en})_2\left(\mathrm{NH}_3\right)_2\right]^{4+}$
(d) $\left[\mathrm{Cr}\left(\mathrm{NH}_3\right)_6\right]^{3+}$
Answer:
(d) $\left[\mathrm{Cr}\left(\mathrm{NH}_3\right)_6\right]^{3+}$
Question 65.
Which of the following complex ion is not expected to absorb visible light?
(a) $\left[\mathrm{Ni}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{3+}$
(b) $\left[\mathrm{Ni}(\mathrm{CN})_4\right]^{2-}$
(c) $\left[\mathrm{Cr}\left(\mathrm{NH}_3\right)_6\right]^{3+}$
(d) $\left[\mathrm{Fe}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+}$
Answer:
(b) $\left[\mathrm{Ni}(\mathrm{CN})_4\right]^{2-}$
Question 66.
The IUPAC name of Zeise's salt is
(a) Tetramminecopper (II) sulphate
(b) FerrousAmmoniumsulphate
(c) Tetracyanocopper (II) Sulphate
(d) Potassiumtrichloro (ethene) platinate (II)
Answer:
(d) Potassiumtrichloro (ethene) platinate(II)

Question 67.
The CFSE is the highest for
(a) $\left[\mathrm{CO} \mathrm{F}_4\right]^{2-}$
(b) $\left[\mathrm{CO}(\mathrm{NCS})_4\right]^{2-}$
(c) $[\mathrm{CO}(\mathrm{NH} 3)]^{3+}$
(d) $\left[\mathrm{CO} \mathrm{Cl}_4\right]^{2-}$
Answer:
(d) $\left[\mathrm{CO} \mathrm{Cl}_4\right]^{2-}$
Question 68.
Zero magnetic moment will be shown by the compound
(a) $\left[\mathrm{Cr}\left(\mathrm{NH}_3\right)_6\right]^{3+}$
(b) $\left[\mathrm{Ag}(\mathrm{CN})_2\right]^{-1}$
(c) $\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{3-}$
(d) $\left[\mathrm{COF}_6\right]^{3-}$
Answer:
(b) $\left[\mathrm{Ag}(\mathrm{CN})_2\right]^{-1}$
Question 69.
The change of $\mathrm{Fe}$ in $\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{3-}$ is .............
(a) -6
(b) +3
(c) -3
(d) +6
Answer:
(A) +3
Question 70.
Coordination number of $\mathrm{Co}$ in $\left[\mathrm{CO}(\mathrm{F})_6\right]^{3-}$ is
(a) 3
(b) 6
(c) 8
(d) 9
Answer:
(b) 6

Question 71.
$\mathrm{AgCl}$ precipitate dissolves in ammonium hydroxide due to the formation of
(a) $\left[\mathrm{Ag}\left(\mathrm{NH}_4\right)_2\right] \mathrm{OH}$
(b) $\left[\mathrm{Ag}\left(\mathrm{NH}_4\right)_2\right] \mathrm{C} 1$
(c) $\left[\mathrm{Ag}\left(\mathrm{NH}_3\right)_2\right] \mathrm{Cl}$
(d) $\left[\mathrm{Ag}\left(\mathrm{NH}_3\right)_2\right]^{+1}$
Answer:
(c) $\left[\mathrm{Ag}\left(\mathrm{NH}_3\right)_2\right] \mathrm{Cl}$
Question 72.
The complexes $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_6\right]\left[\mathrm{Cr}(\mathrm{CN})_6\right]$ and $\left[\mathrm{Cr}\left(\mathrm{NH}_3\right)_6\right]\left[\mathrm{CO}(\mathrm{CN})_6\right]$ are the example of which type of isomerism?
(a) Linkage isomerism
(b) Ionisation isomerism
(c) Optical isomerism
(d) Coordination isomerism
Answer:
(d) Coordination isomerism
Question 73.
A magnetic moment at $1.73 \mathrm{BM}$ will be shown by one among the following?
(a) $\mathrm{Ti} \mathrm{Cl}_4$
(b) $\left[\mathrm{Co} \mathrm{Cl}_6\right]^{4-}$
(c) $\left[\mathrm{CU}\left(\mathrm{NH}_3\right) 4\right]^{2+}$
(d) $\left[\mathrm{N}(\mathrm{CN})_4\right]^2$
Answer:
(c) $\left[\mathrm{CU}\left(\mathrm{NH}_3\right) 4\right]^{2+}$
Question 74.
Among the following complexes which one shows zero CFSE?
(a) $\left[\mathrm{Mn}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{3+}$
(b) $\left[\mathrm{Fe}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{3+}$
(c) $\left[\mathrm{CO}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+}$
(d) $\left[\mathrm{CO}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{3+}$
Answer:
(b) $\left[\mathrm{Fe}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{3+}$

Question 75.
Number of possible isomers for the complex $\left[\mathrm{CO}(\mathrm{en})_2 \mathrm{Cl}_2\right] \mathrm{Cl}$ will be
(a) 1
(b) 4
(c) 3
(d) 2
Answer:
(c) 3
Question 76.
The hybridization involved in the complex $\left[\mathrm{Ni}(\mathrm{CN})_4\right]^{2-}$ is
(a) $\mathrm{sp}^3$
(b) $\mathrm{d}^2 \mathrm{sp}^{3+}$
(c) $\mathrm{dsp}^2$
(d) $\mathrm{sp}^3 \mathrm{~d}^2$
Answer:
(c) $\mathrm{dsp}^2$
II. Fill in the blanks:
Question 1.

The reaction between Ferric chloride and potassium thio cyanate solution gives a blood red coloured coordination compound as
Answer:
$\mathrm{K}_3\left[\mathrm{Fe}(\mathrm{SCN})_6\right]$ Potassium ferrithio cyanate
Question 2. is a pigment present in plants acting as a photosensitiser in the photosynthesis.
Answer:
Chlorophyll
Question 3.
In a coordination compound, if the metal ion has a secondary valence of six, it has an ..................... geometry.
Answer:
Octahedral
Question 4.
The coordination polyhedral of $\left[\mathrm{Ni}(\mathrm{CO})_4\right]$ is .......................
Answer:
Tetrahedral

Question 5.
In $\left[\mathrm{Ni}(\mathrm{en})_3\right] \mathrm{Cl}_2$, the coordination number of $\mathrm{Fe}^{2+}$ is ..............
Answer:
6
Question 6.
In the coordination entity $\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{4-}$, the oxidation state of iron is represented as .....................
Answer:
II
Question 7.
The oxidation state of cobalt in $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_5 \mathrm{Cl}\right]^{2+}$ is. .....................
Answer:
+3
Question 8.
The coordination number of $\mathrm{Pt}$ in $\left[\mathrm{Pt}\left(\mathrm{NO}_2\right)\left(\mathrm{H}_2 \mathrm{O}\right)\left(\mathrm{NH}_3\right)_2\right] \mathrm{Br}$ is .......................
Answer: 
4
Question 9.
Ethylene diamine tetraacetate has the structure as ................
Answer:

Question 10 .
The IUPAC name of $\mathrm{k}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right]$ is .................
Answer:
Potassium hexacyanido $-\mathrm{kC}$ ferrate (II)
Question 11.
The complex ion in $\mathrm{k}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right]$ is ..................
Answer:
$\left[\mathrm{Fe}(\mathrm{CN})_2\right]^{4-}$
Question 12.
The oxidtion state of $\mathrm{Fe}$ in $\mathrm{k}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right]$ is ...................
Answer:
II
Question 13.
The coordination number of cobalt in $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_4 \mathrm{Cl}_2\right] \mathrm{Cl}$ is ................
Answer:
6
Question 14.
The IUPAC name of $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_4 \mathrm{Cl}_2\right] \mathrm{Cl}$ is ...............
Answer:
Tetra ammine dichlorido cobalt (III) chloride
Question 15.
The IUPAC name of $\left[\mathrm{Cr}(\mathrm{en})_3\right]\left[\mathrm{Cr}_6\right]$ is ..................
Answer:
Tris (ethane -1,2- diamine) chromium (III) hexa fluorido chromate (III)
Question 16.
The coordination number of $\left[\mathrm{Cr}(\mathrm{en})_3\right]\left[\mathrm{Cr}_6 \mathrm{~F}_6\right]$ and oxidation state of $\mathrm{Cr}_r$ are .....................
Answer: 
$6,+3$
Question 17.
The IUPAC name of $\left[\mathrm{Cr}\left(\mathrm{NH}_3\right)_3\right]\left(\mathrm{H}_2 \mathrm{O}_3\right] \mathrm{Cl}_3$ is .......................
Answer:
Triamminetriaquachromium(III) chloride

Question 18 .
The coordination number of $\mathrm{Fe}$ in $\mathrm{K}_3\left[\mathrm{Fe}(\mathrm{CN})_5 \mathrm{NO}\right]$ is ................
Answer:
6
Question 19.
The IUPAC name of $\left[\mathrm{Fe}_6\right]^{4-}$ is ...................
Answer:
Hexafluriodoferrate(II)ion
Question 20.
The coordination number of cobalt in $\left[\mathrm{CO}\left(\mathrm{NO}_2\right)_3\left(\mathrm{NH}_3\right)_3\right]$ is ................
Answer:
6
Question 21.
The IUPAC name of coordination compound $\left[\mathrm{CO}\left(\mathrm{NO}_2\right)_3\left(\mathrm{NH}_3\right)_3\right]$ is ...............
Answer:
Triamminetrinitrito $-\mathrm{K}$ NCobalt (III)
Question 22.
The isomerism possible in $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_5\left(\mathrm{NO}_2\right)\right]^{2+}$ is ......................
Answer:
Linkage isomerism
Question 23.
The isomerism possible in $\left[\mathrm{Pt}(\mathrm{en})_2 \mathrm{Br}_2\right] \mathrm{Cl}_2$ is. .....................
Answer:
Ionisation isomerism
Question 24.
The type of isomerism possible in $\mathrm{CrCl}_3 6 \mathrm{H}_2 \mathrm{O}$ is ....................
Answer:
Solvate isomerism
Question 25.
Geometric isomerism exists in .............. complexes due to different possible three dimensional spatial arrangement of ligands around the central metal atom.
Answer:
Heteroleptic
Question 26.
..................... In of the form $\left[\mathrm{MA}_2 \mathrm{~B}_2\right]^{\mathrm{n \pm}}$, cis-trans isomerism exists.
Answer:
Square planar complexes

Question 27.
The square planar complex of the type $\left[\mathrm{M}(\mathrm{xy})_2{ }^{\mathrm{n} \pm}\right]$ shows .............. isomerism.
Answer:
Geometrical (or) cis-trans
Question 28.
$\left[\mathrm{Pt}\left(\mathrm{NH}_3\right)_2 \mathrm{Cl}_2\right]^{2+}$ shows ................. isomerism.
Answer:
Cis-trans isomerism
Question 29.
$\left[\mathrm{CO} \mathrm{Cl}_2(\mathrm{en})_3\right]^{3+}$ exhibits ................... isomerism.
Answer:
Optical isomerism
Question 30.
The hybridised orbitals are and their orientation in space gives a definite ...................... to the complex ion.
Answer:
Directional, Geometry
Question 31.
The shape of $\left[\mathrm{Fe}(\mathrm{CO})_5\right]$ is ..................
Answer:
Trigonal bipyramidal
Question 32 .
The shape of $\left[\mathrm{Ni}(\mathrm{CO})_4\right]$ is whereas the shape of $\left.\left[\mathrm{Ni}(\mathrm{CN})_4\right)\right]^{2+}$ is ................
Answer:
Tetrahedral, Square planar
Question 33.
The shape of $\left[\mathrm{Hgl}_3\right]^{-}$is and the type of hybridisation is .....................
Answer:
Trigonal planar, $\mathrm{sp}^2$
Question 34.
The geometry and hybridisation involvedin $\left[\mathrm{CuCl}_2\right]^{-}$are............................ respectively.
Answer:
Linear, $s p$

Question 35.
The hybridisation and geometry of $\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{2-}$ and $\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{3-}$ are .................... and .................... respectively
Answer:
$\mathrm{d}^2 \mathrm{sp}^3$, octahedral
Question 36.
The shape of $\left[\mathrm{Fe}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+}$ and $\left[\mathrm{COF}_6\right]^{4-}$ is ..................
Answer:
Octahedral
Question 37.
The hybridisation take place in $\left[\mathrm{Fe} \mathrm{F}_6\right]^{4-}$ and $\left[\mathrm{Fe}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+}$ is ....................
Answer:
$\mathrm{SP}^3 \mathrm{~d}^2$
Question 38 . 
The $\mathrm{d}$ orbital involved in the dsp 3 hybridisation of $\left[\mathrm{Fe}(\mathrm{CO})_5\right]$ is ....................
Answer:
$\mathrm{d}_z{ }^2$
Question 39.
In the octahedral complexes, if the (n-1)d orbitals are involved in hybridisation, they are called .......................... and ...................... complexes.
Answer:
The inner orbital complexes, low spin complexes (or) Spin paired complexes.
Question 40.
$\mathrm{CO}, \mathrm{CN}^{-}$, en and $\mathrm{NH}_3$ are called ............................. ligands.
Answer:
Strong
Question 41.
The magnetic character of $\left[\mathrm{Ni}(\mathrm{CO})_4\right]$ is ...........................
Answer:
Diamagnetic

Question 42.
The hybridisation and geometry of $\left[\mathrm{Ni}(\mathrm{CO})_4\right]$ are ...................... and ....................... respectively.
Answer:
$\mathrm{SP}^3$, tetrahedral
Question 43.
The hybridisation and magnetic nature of $\left[\mathrm{Ni}(\mathrm{CN})_4\right]^{2-}$ are................... and ..................respectively.
Answer; dsp $^2$, diamagnetic
Question 44.
The hybridisation and magnetic nature of $\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{3-}$ are .......................... and .......................... respectively.
Answer:
$\mathrm{d}^2 \mathrm{sp}^3$, paramagnetic
Question 45.
The number of unpaired electrons in $\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{3 \text { - }}$ is and the magnetic moment value is .................
Answer:
$1,1.73 \mathrm{BM}$
Question 46.
The hybridisation and geometry of $\left[\mathrm{CoF}_6\right]^{3-}$ are .............................. and ..............................respectively
Answer: $\mathrm{sp}^3 \mathrm{~d}^2$, octahedral
Question 47.
The number of unpaired electrons and magnetic moment value of $\left[\mathrm{Co}_6\right]^{3-}$ are ..................and .................... respectively.
Answer:
$4,4.899 \mathrm{BM}$
Question 48.
The spin only magnetic moment of tetrachlorido manganate (II) ion is ....................
Answer:
$5.9 \mathrm{BM}$

Question 49.
$\left[\mathrm{Co}(\mathrm{en})_2 \mathrm{Cl}_2\right] \mathrm{Br}$ react with silver nitrate to form .................... coloured precipitate.
Answer:
Pale Yellow
Question 50 .
The crystal field splitting energy of $\mathrm{Ti}^{3+}$ ion complexes such as $\left[\mathrm{TiBr}_6\right]^{3-},\left[\mathrm{TiF}_6\right]^{3-},\left[\mathrm{Ti}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{3+}$ the ligands are in the order ....................
Answer:
$
\mathrm{Br}^{-}<\mathrm{F}^{-}<\mathrm{H}_2 \mathrm{O}
$
Question 51.
................... is defined as the energy difference of electronic configuration in the ligand field and the isotropic field.
Answer:
Crystal Field stabilisation energy
Question 52.
The hydrated copper (II) ion is in colour as it absorbs............................. light and transmit its complementary colour.
Answer:
Blue, Orange
Question 53.
The colour of $\left[\mathrm{Ti}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{3+}$ is..........................
Answer:
purple
Question 54.
....................... is a complex of copper (II) ion used in printing ink and in the packaging industry.
Answer:
Phthalo blue - a bright blue pigment
Question 55.
Purification of Nickel by ........................ process involves formation ............................. which. yields $99.5 \%$ pure Nickel on decomposition.
Answer:
Mond's, $\left[\mathrm{Ni}(\mathrm{CO})_4\right]$
Question 56.
.............................. is used as a chelating ligand for the separation of lanthanides, in softening of hard water and also in removing poisoning.
Answer:
EDTA, Lead

Question 57.
.................... process is used in the extraction of silver and gold from their ores.
Answer:
Mac - Arthur - Forrest cyanide
Question 58 .
Wilkinson's catalyst ...................... is used for hydrogenation of alkenes.
Answer:
$\left[\left(\mathrm{P} \mathrm{Ph}_3\right)_3 \mathrm{Rh} \mathrm{Cl}\right]$
Question 59.
........................ is used in the polymerisation of ethane as a complex catalyst
Answer:
Ziegler - Natta catalyst (or) $\left[\mathrm{TiCl}_4\right]+\mathrm{Al}\left(\mathrm{C}_2 \mathrm{H}_5\right)_3$

Question 60

.................... is used as antitumor drug in cancer treatment.
Answer:
Cis - Platin
Question 61 .
In photography, undecomposed $\mathrm{AgBr}$ forms a soluble complex called ....................
Answer:
Sodium dithio sulphato argentate(I)
Question 62.
Ared blood corpuscles (RBC) is composed of heme group which ................. complex play an important role in carrying oxygen from lungs to tissues.
Answer:
$\mathrm{Fe}^{2+}$ Porphyrin
Question 63 .
The green pigment chlorophyll contains ion surrounded by a modified porphyrin ligand called ......................
Answer:
$\mathrm{Mg}^{2+}$, corrinring
Question 64.
$\mathrm{CO}^{3+}$ is present in vitamin $\mathrm{B}_{12}$ otherwise chemically called ..................
Answer:
Cyanocobalamine
Question 65 .
The enzyme important in digestion is ....................... contains .......................... coordinated to protein
Answer:
Carboxy peptidase, $\mathrm{Zinc}$ ion $\left(\mathrm{Zn}^{2+}\right)$ Match the following

III. Match the following
Match the List I and List II using the code given below the 1sit
Question 1.

Answer:
(a) $3,4,1,2$
Question 2.

Answer:
(b) $3,1,4,2$
Question 3.

Answer:
(a) 2, 1, 4, 3
Question 4.

Answer:
(c) $3,4,2,1$
Question 5.

Answer:
(a) $3,4,1,2$
Question 6.

Answer:
(b) $2,3,4,1$
Question 7.

Answer:
(a) $4,3,2,1$
Question 8 .

Answer:
(a) $2,3,4,1$
Question 9.

Answer:
(c) $3,1,4,2$
Question 10 .

Answer:
(c) $3,1,4,2$
IV. Assertion and Reason
Question 1.

ASSertiOfl (A) - Mohr's Salt answers the presennee of $\mathrm{Fe}^{2+}, \mathrm{NH}_4{ }^{2-}$ and $\mathrm{SO}_4{ }^{2-}$ ions.
Reason (R) - The double salt, Mohr's salt loose their identity and dissociates into their constituent simple ions in solution.
(a) Both $\mathrm{A}$ and $\mathrm{R}$ arc correct and $\mathrm{R}$ is the correct explanation of $\mathrm{A}$.
(b) Both $\mathrm{A}$ and $\mathrm{R}$ are correct but $\mathrm{R}$ is not the correct explanation of $\mathrm{A}$.
(c) Both $\mathrm{A}$ and $\mathrm{R}$ are wrong.
(d) $\mathrm{A}$ is wrong but $\mathrm{R}$ is correct.
Answer:
(a) Both $\mathrm{A}$ and $\mathrm{R}$ are correct and $\mathrm{R}$ is the correct explanation of $\mathrm{A}$.
Question 2.
Assertion (A) - Potassium ferro thiocyanate answers the presences of $\mathrm{Fe}^{3+}, \mathrm{K}^{+}$and $\mathrm{SCN}^{-}$ions.
Reason (R) - The complex ion in coordination compound does not loose its identity and never dissociate to give simple ions.
(a) Both $\mathrm{A}$ and $\mathrm{R}$ are correct and $\mathrm{R}$ is the correct explanation of $\mathrm{A}$.
(b) Both $\mathrm{A}$ and $\mathrm{R}$ are correct but $\mathrm{R}$ is not the correct explanation of $\mathrm{A}$.
(c) $\mathrm{A}$ is wrong but $\mathrm{R}$ is correct.
(d) Both $\mathrm{A}$ and $\mathrm{R}$ are wrong.
Answer:
(c) $\mathrm{A}$ is wrong but $\mathrm{R}$ is correct.
Question 2.

Assertion (A) - The outer sphere in the complex compound is called ionisation sphere.
Reason (R) - The groups prcscnt in outer sphere are loosely bound to the central metal ion and hence can be separated into ions upon dissolving the complex in the suitable solvent.
(a) Both $\mathrm{A}$ and $\mathrm{R}$ are correct and $\mathrm{R}$ is the correct explanation of $\mathrm{A}$.
(b) Both $\mathrm{A}$ and $\mathrm{R}$ are correct but $\mathrm{R}$ is not the correct explanation of $\mathrm{A}$.
(c) $A$ is correct but $R$ is wrong.
(d) $A$ is wrong but $R$ is correct.
Answer:
(a) Both $\mathrm{A}$ and $\mathrm{R}$ are correct and $\mathrm{R}$ is the correct explanation of $\mathrm{A}$.

Question 8.
Assertion (A) - Geometrical isomerism exists in homoleptic complexes.
Reason (R) - In homoleptic complexes due to different possible three dimensional spatial arrangements of ligands around the central metal atoms.
(a) Both $A$ and $R$ are correct and $R$ is the correct explanation of $A$.
(b) Both $\mathrm{A}$ and $\mathrm{R}$ are correct but $\mathrm{R}$ is not the correct explanation of $\mathrm{A}$.
(c) $A$ and $R$ are wrong.
(d) $\mathrm{A}$ is correct but $\mathrm{R}$ is wrong
Answer:
(c) $A$ and $R$ are wrong.
Question 9.
Assertion (A) - Geometrical isomerism exists in heteroleptic complexes.
Reason (R) - In heteroleptic complexes due to different possible three dimensional spatial arrangement of ligands around the central metal atom results in geometrical isomers.
(a) Both $\mathrm{A}$ and $\mathrm{R}$ are correct and $\mathrm{R}$ is the correct explanation of $\mathrm{A}$.
(b) Both $\mathrm{A}$ and $\mathrm{R}$ are correct but $\mathrm{R}$ is not the correct explanation of $\mathrm{A}$.
(c) Both $\mathrm{A}$ and $\mathrm{R}$ are wrong.
(d) $A$ is correct but $R$ is wrong.
Answer:
(a) Both $\mathrm{A}$ and $\mathrm{R}$ are correct and $\mathrm{R}$ is the correct explanation of $\mathrm{A}$.
Question 10.
Assertion (A) $-\left[\mathrm{Ni}(\mathrm{CO})_4\right]$ is diamagnetic
Reason $(\mathrm{R})-\mathrm{In}\left[\mathrm{Ni}(\mathrm{CO})_4\right]$, there is no unpaired electrons and so it is diamagnetic.
(a) Both $\mathrm{A}$ and $\mathrm{R}$ are wrong.
(b) $A$ is correct but $R$ is wrong
(c) Both $\mathrm{A}$ and $\mathrm{R}$ are correct and $\mathrm{R}$ is the correct explanaiton of $\mathrm{A}$.
(d) Both $\mathrm{A}$ and $\mathrm{R}$ are correct but not $\mathrm{R}$ is the correct explanaiton of $\mathrm{A}$.
Answer:
(c) Both $\mathrm{A}$ and $\mathrm{R}$ are correct and $\mathrm{R}$ is the correct explanaiton of $\mathrm{A}$.
Question 11 .
Assertion (A) $-\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{3-}$ is paramagnetic
Reason $(\mathrm{R})-\mathrm{In}\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{3-}$, there is one unpaired electron and so it is paramagnetic
(a) Both $\mathrm{A}$ and $\mathrm{R}$ are correct and $\mathrm{R}$ is the correct explanation of $\mathrm{A}$,
(b) Both $\mathrm{A}$ and $\mathrm{R}$ are correct but $\mathrm{R}$ is not the correct explanation of $\mathrm{A}$.
(e) Both $\mathrm{A}$ and $\mathrm{R}$ are wrong.
(d) $A$ is correct but $R$ is wrong.
Answer:
(a) Both $\mathrm{A}$ and $\mathrm{R}$ are correct and $\mathrm{R}$ is the correct explanation of $\mathrm{A}$.

Question 12 .
Assertion (A) - Most of the transition complexes are coloured.
Reason (R) - Transition complexes absorbs the light of particular wavelength in the visible light. The transmitted light gives the complementary colour.
(a) Both $\mathrm{A}$ and $\mathrm{R}$ are correct and $\mathrm{R}$ is the correct explanation of $\mathrm{A}$.
(b) $A$ is correct but $R$ is wrong.
(e) $A$ and $R$ are wrong.
(d) $\mathrm{A}$ is wrong but $\mathrm{R}$ is correct.
Answer:
(a) Both $\mathrm{A}$ and $\mathrm{R}$ are correct and $\mathrm{R}$ is the correct explanation of $\mathrm{A}$.
Question 13.
Assertion (A) - Complexes of central metal atom such as of $\mathrm{Cu}^{+}, \mathrm{Zn}^{2+}, \mathrm{SC}^{3+}, \mathrm{Ti}^{4+}$ are colourless.
Reason $(\mathrm{R})-\mathrm{Cu}^{+}, \mathrm{Zn}^{2+}, \mathrm{SC}^{3+}, \mathrm{Ti}^{4+}$ are having $\mathrm{d}^0$ or $\mathrm{d}^{10}$ configuration and because of it, $\mathrm{d}-\mathrm{d}$ transition is not possible and so they are colourless.
(a) Both $\mathrm{A}$ and $\mathrm{R}$ are correct and $\mathrm{R}$ is the correct explanation of $\mathrm{A}$.
(b) Both $\mathrm{A}$ and $\mathrm{R}$ are correct and $\mathrm{R}$ is not correct explanation of $\mathrm{A}$.
(c) Both $\mathrm{A}$ and $\mathrm{R}$ arc wrong.
(d) $A$ is correct but $R$ is wrong.
Answer:
(a) Both $\mathrm{A}$ and $\mathrm{R}$ are correct and $\mathrm{R}$ Is the correct explanation of $\mathrm{A}$.
V. Find the Odd one out.
Question 1.

(a) Vitamin $-\mathrm{B}_{12}$
(b) Haemoglobin
(c) Chlorophyll
(d) Glycine
Answer:
(d) Glycine is an amino acid whereas others are complex salts.
Question 2.
(a) Mohr's salt
(b) Potassium Ferrocyanide
(c) Potassium ferrithio cyanate
(d) Wilkinson's compound
Answer:
(a) Mohr's salt is a double salt whereas others are complex salts.

Question 3.
(a) $\left[\mathrm{CO}\left(\mathrm{NH}_3\right) 6\right]^{3+}$
(b) $\left[\mathrm{Fe}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+}$
(c) $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_3 \mathrm{Cl}_3\right]$
(d) $\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{+3}$
Answer:
(e) It is heteroleptic complex whereas others are homoleptic complex.
Question 4.
(a) $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_5 \mathrm{Cl}\right]^{2+}$
(b) $\left[\mathrm{Pt}\left(\mathrm{NH}_3\right)_2 \mathrm{CI},\right]^{2+}$
(c) $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_6\right]^{3+}$
(d) $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_3 \mathrm{CI}_3\right]$
Answer:
(c) It $\mathrm{iS}$ homoleptic complex whereas others are heteroleptic complexes.
Question 5 .
(a) $\mathrm{NH}_3$
(b) $\mathrm{CN}$
(c) $\mathrm{H}_2 \mathrm{O}$
(d) $\mathrm{PPh}_3$
Answer:
(b) It is a negative ligand whereas others are neutral ligands
Question 6 .
(a) $\mathrm{CN}^{-}$
(b) $\mathrm{CI}^{-}$
(c) $\mathrm{SO}_4^{2-}$
(d) $\mathrm{NH}_3$
Answer:
(d) It is a neutral ligand whereas others are negative ligands.

Question 7.
(a) $\mathrm{K}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right]$
(b) $\mathrm{Na}\left[\mathrm{Ag}(\mathrm{CN})_2\right]$
(c) $\mathrm{K}_2\left[\mathrm{Zn}(\mathrm{CN})_4\right]$
$\left(\mathrm{d}\left[\mathrm{Cu}\left(\mathrm{NH}_3\right)_4\right] \mathrm{SO}_4\right.$
Answer:
(d) It is a cationic complex whereas others are anionic complexes.
Question 8 .
(a) $\mathrm{K}_3\left[\mathrm{Fe}(\mathrm{CN})_6\right]$
(b) $\left[\mathrm{Cu}\left(\mathrm{NH}_3\right)_4\right] \mathrm{SO}_4$
(c) $\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)\right] \mathrm{Cl}_3$
(d) $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_4 \mathrm{CI}_2\right] \mathrm{Cl}$
Answer:
(a) It is an anionic complex whereas others are cationic complexes.
Question 9.
(a) $\left[\mathrm{Ti}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{3+}$
(b) $\left[\mathrm{Fe}(\mathrm{CO})_5\right]$
(c) $\left[\mathrm{FeF}_6\right]^{4-}$
(d) $\left[\mathrm{COF}_6\right]^{4-}$
Answer:
(b) $\mathrm{Fe}(\mathrm{CO}) \mathrm{I}$ has trigonalbipyramidal shape whereas others have octahedral shape.
Question 10 .
(a) $\left[\mathrm{Ag}(\mathrm{CN})_2\right]^{-}$
(b) $\left[\mathrm{Fe}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+}$
(c) $\left[\mathrm{Fe} \mathrm{F}_6\right]^{4-}$
(d) $\left[\mathrm{CO} \mathrm{F}_6\right]^{4-}$
Answer:
(a) $\left[\mathrm{Ag}(\mathrm{CN})_2\right]$ is linear in shape whereas others arc in octahedral shape.
VI. Find out the correct pair
Question 1.

(a) $\left[\mathrm{Ni}(\mathrm{CO})_4\right],\left[\mathrm{Ni} \mathrm{Cl}_4\right]^{2-}$
(b) $\left[\mathrm{Cu} \mathrm{Cl}_2\right],\left[\mathrm{Fe}(\mathrm{CO})_5\right]$
(c) $\left[\mathrm{Fe} \mathrm{F}_6\right]^{4-},\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{2-}$
(d) $\left[\mathrm{Ni}(\mathrm{CO})_4\right],\left[\mathrm{HgI}_3\right]^{-}$
Answer:
(a) It is tetrahedral whereas others have different shapes.

Question 2.
(a) $\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{3-},\left[\mathrm{COFF}_6\right]^{3-}$
(b) $\left[\mathrm{Ni}(\mathrm{CN})_4\right]^{2-},\left[\mathrm{Ni}(\mathrm{CO})_5\right]$
(c) $\left[\mathrm{Fe} \mathrm{F}_6\right],\left[\mathrm{CO} \mathrm{F}_6\right]^{3-}$
(d) $\left[\mathrm{Cu} \mathrm{Cl}_2\right],\left[\mathrm{HgI}_3\right]^{-}$
Answer:
(a) It is paramagnetic pair whereas others are different.
Question 3.
(b) $\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_5 \mathrm{Cl}\right] \mathrm{Cl}_2 \cdot \mathrm{H}_2 \mathrm{O}$ and $\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right] \mathrm{Cl}_3$
(c) $\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_4 \mathrm{Cl}_2\right] \mathrm{Cl} .2 \mathrm{H}_2 \mathrm{O}$ and $\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_5 \mathrm{Cl}\right] \mathrm{Cl}_2 \cdot \mathrm{H}_2 \mathrm{O}$
(d) $\left[\mathrm{Fe}(\mathrm{CO})_5\right]$ and $\left[\mathrm{Ni}(\mathrm{CN})_4\right]_2$
Answer:
(d) $\left[\mathrm{Fe}(\mathrm{CO})_5\right]$ and $\left[\mathrm{Ni}(\mathrm{CN})_4\right]^{2-}$ Others are solvate isomersim.
VII. Find out the incorrect pair
Question 1.

(a) $\left[\mathrm{Fe}\left(\mathrm{F}_6\right)\right]^{4-},\left[\mathrm{CO} \mathrm{F}_6\right]^{4-}$
(b) $\left.[\mathrm{Cu} \mathrm{CI}]_2\right]^{-},\left[\mathrm{Ag}(\mathrm{CN})_2\right]^{-}$
(c) $\left[\mathrm{Ni}(\mathrm{CN})_4\right] 2,\left[\mathrm{Pt}\left(\mathrm{NH}_3\right)_4\right]^2$
(d) $\left[\mathrm{HgI}_3\right]^{-},\left[\mathrm{Fe}(\mathrm{CO})_5\right]$
Answer:
(d) $\left[\mathrm{HgI}_3\right]^{-},\left[\mathrm{Fe}(\mathrm{CO})_5\right]$
Question 2.
(a) $\mathrm{CN}^{-}$and $\mathrm{NO}_2^{-}$
(b) $\mathrm{CO}$ and $\mathrm{NO}$
(c) $\mathrm{F}^{-}$and $\mathrm{Br}$
(d) en and $\left(\mathrm{COO}^{-}\right)_2$
Answer:
(a) $\mathrm{CN}$ and $\mathrm{NO}_2$. Others are weak ligands.
2 Marks Questions and Answers
Question 1.

What is the limitations of Werner's theory?
Answer:
Werner's theory was able to explain a number of properties of coordination compounds, it does not explain their colour and magnetic properties.

Question 2 .
Differentiate primary valency and secondary valency.
Answer:
Primary Valency:
1. The primary valence of a metal ion positive in most of the cases and zero in certain cases.
2. The primary valence is always satisfied by negative ions.
3. The primary valences are non directional
Secondary Valency:
1. The secondary valence as the coordination number.
2. The secondary valence is satisfied by negative ions, neutral molecular or positive ions.
3. The secondary valences are directional
Question 3.
What is coordination entity? Give example.
Answer:
Coordination entity is an ion or a neutral molecule composed of a central action, usually a metal and the array of other groups of atoms (ligands) that are attached to it. For e.g; in potassium ferrocyanide $\mathrm{K}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right]$ the coordination entity is $\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{4-}$.
Question 4.
What is meant by central action in complex salt?
Answer:
The central atom / ion is the one that occupies the central position in a coordination entity and binds other atoms or group of atoms (ligands) to itself, through a coordinate covalent bond. For e.g; In $\mathrm{K} 4\left[\mathrm{Fe}(\mathrm{CN})_6\right]$ the central metal ion is $\mathrm{Fe}^{2+}$.
Question 5.
What are ligands? Give example.
Answer:
The ligands are the atoms or groups of atoms bound to the central metal atom / ion. The atom in a ligand that is bound directly to the central metal atom is known as donor atom. For e.g; $\mathrm{In}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right]$ the ligand is $\mathrm{CN}$ ion but the donor atom is carbon.
Question 6.
What is meant by coordination sphere? Give example.
Answer:

The complex ion at the coordination compound containing the central metal atom / ion and the ligands attached to it, is collectively called coordination sphere and are usually enclosed in square brackets with the net charge. For e.g; The coordination compound $\mathrm{K}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right]$ contains the complex ion $\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{4-}$ is referred as coordination sphere.
Question 7.
What is meant by coordination polyhedron?
Answer:
The three dimensional spatial arrangement of ligand molecules / ions that are directly attached to the central metal atom is known as coordination polyhedron (Polygon). For e.g; $\operatorname{In} \mathrm{K}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right]$ the coordination polyhedra is octahedral.
Question 8.
Define coordination number? Give example
Answer:
The number of ligand donor atoms bonded to a central metal ion in a complex is called the coordination number
of a metal. In other words, the coordination number is equal to the number of o bonds between ligands and the central metal atom. For e.g; $\mathrm{In}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right]$ the coordination number of $\mathrm{Fe}^{2+}{ }^{2+}+6$.
Question 9.
What is the coordination number in $\left[\mathrm{Ni}(\mathrm{en})_3\right] \mathrm{Cl}_2$ ? Explain it.
Answer:
In $\left[\mathrm{Ni}(\mathrm{en})_3\right] \mathrm{Cl}_2$, the coordination number of $\mathrm{Ni}^{2+}$ is also 6. The ligand "en" represents ethane -1,2-diamine $\left(\mathrm{H}_2 \mathrm{~N}-\mathrm{CH}_2-\mathrm{CH}_2-\mathrm{NH}_2\right)$ and it contains two donor atoms (Nitrogen). Each ligand forms two coordination bonds with nickel. So, totally there are six coordination bonds between them.
Question 10.
Calculate the oxidation number of $\mathrm{CO}$ in $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_5 \mathrm{Cl}\right]^{2+}$.
Answer:
In $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_5 \mathrm{Cl}\right]^{2+}$ let the oxidation number of cobalt is $\mathrm{x}$. The net charge $=+2=\mathrm{x}+5(0)+1(-1)$
$\mathrm{x}-1=+2$
$\therefore \mathrm{x}=+3$
Question 11.
Explain about the types of coordination compound based on kind of ligands?
Answer:
1. A coordination compound in which the central metal ion / atom is coordinated to only one kind of ligands is called homoleptic complex, e.g; $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_6\right]^{3+}$

2. The central metal ion/atom is coordinated to more than one kind of ligands is called a heteroleptic complex, e.g; $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_5 \mathrm{Cl}\right]^{2+}$
Question 12 .
Write the IUPAC names of the following complex salts.
1. $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_6\right] \mathrm{Cl}_3$
2. $\mathrm{K}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right]$
Answer:
1. $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_6\right] \mathrm{Cl}_3-$ Hexaamminecobalt (III) Chloride
2. $\mathrm{K}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right]-$ Potassiumhexacyanido $-\mathrm{K} \mathrm{C}$ ferrate (II)
Question 13.
Give the formula and IUPAC name of the following ligands.
(i) $\mathrm{OX}$
(ii) en
Answer:

(i) 

(ii) 

Question 14.
Give the formula of
1. EDTA
2. Triphenyl phosphine
Answer:
1. EDTA

2. Triphenyl phosphine $-\mathrm{P}(\mathrm{Ph})$
Question 15.
Give the IUPAC names of the following compounds.
1. $\left[\mathrm{PdI}_2(\mathrm{ONO})_2\left(\mathrm{H}_2 \mathrm{O}\right)_2\right]$
2. $\left[\mathrm{Cr}\left(\mathrm{PPh}_3\right)(\mathrm{CO})_5\right]$
Answer:
1. $\left[\mathrm{Pd} \mathrm{I}_2(\mathrm{ONO})_2\left(\mathrm{H}_2 \mathrm{O}\right)_2\right]$ - Diaquadiiododinitrito - kopalladium (iv)
2. $\left[\mathrm{Cr}\left(\mathrm{PPh}_3\right)(\mathrm{CO})_5\right]$ - Pentacarbonyltriphenylphosphanechromium (O)
Question 16.
Give the IUPAC names of the following compounds.
1. $\left[\mathrm{CO}\left(\mathrm{NO}_2\right)_3\left(\mathrm{NH}_3\right)_3\right]$
2. $\mathrm{K}_3\left[\mathrm{Fe}(\mathrm{CN})_5 \mathrm{NO}\right]$
Answer:
1. $\left[\mathrm{CO}\left(\mathrm{NO}_2\right)_3\left(\mathrm{NH}_3\right)_3\right]$ - Triamminetrinitrioto - $\mathrm{KN}$ Cobalt (III)
2. $\mathrm{K}_3\left[\mathrm{Fe}(\mathrm{CN})_5{ }^{\mathrm{NO}}\right]-$ Potassiumpentacyanidonitrosylferrate (II)

Question 18.
Give the IUPAC names of the following compounds.
1. $\left[\mathrm{Ag}\left(\mathrm{NH}_3\right)_2\right]^{+}$
2. $\left[\mathrm{FeF}_6\right]^{4-}$
Answer:
1. $\left[\mathrm{Ag}\left(\mathrm{NH}_3\right)_2\right]^{+}-$Diammine silver (I) ion
2. $\left[\mathrm{FeF}_6\right]^{4-}-\mathrm{Hexa}$ fluoro ferrate (II) ion.
Question 19.
Define isomerism in coordination compounds.
Answer:
Isomerism is the phenomenon in which more than one coordination compounds having the same molecular formula have different physical and chemical properties due to different arrangement of ligands around the central metal atom.
Question 20.
What are the different types of isomerism in coordination compounds?
Answer:

Question 21.
Define stereo isomerism in coordination compound. Give its type.
Answer:
The phenomenon in which the coordination compounds have the same chemical formula and connectivity between the central metal atom and the ligands is known as stereo isomerism. But they differ in the spatial arrangement of ligands in three dimensional space. They can be further classified as (a) Geometrical isomerism
(b) Optical isomerism
Question 22.
Define crystal field stabilisation energy. (CFSE).
Answer:
It is defined as the energy difference of electronic configurations in the ligand field $\left(E_{L F}\right)$ and the isotropic field $/$ barycentre $\left(\mathrm{E}_{\text {iso }}\right)$
$\operatorname{CFSE}\left(\Delta \mathrm{E}_0\right)=\left\{\mathrm{E}_{\mathrm{LF}}\right\}-\left\{\mathrm{E}_{\text {iso }}\right\}$
$\left.=\left\{\left[\mathrm{n}_{\mathrm{t} 2 \mathrm{~g}}-(0.4)+\mathrm{n}_{\mathrm{eg}}(0.6)\right] \Delta_0+\mathrm{n}_{\mathrm{p}} \mathrm{P}\right]-\mathrm{n}_{\mathrm{p}} \mathrm{P}\right\}$
Where,
$\mathrm{n}_{\mathrm{t} 2 \mathrm{~g}}=$ the number of electrons in $\mathrm{t},$, , orbital.
$\mathrm{n}_{\mathrm{eg}}=$ the number of electrons in $\mathrm{n}$ orbital
$\mathrm{n}_{\mathrm{p}}=$ number of electron pairs in the ligand field.
$\mathrm{n}_{\mathrm{p}}=$ number of electron pairs in the iso tropic field.
Question 23.
What are metallic carbonyl? Give example.
Answer:
Metal carbonyls are the transition metal complexes of carbon monoxide, containing metal carbon bond. In these complexes $\mathrm{CO}$ molecule act as a neutral ligand, e.g $-\left[\mathrm{Ni}(\mathrm{CO})_4\right]$ Nickel tetra carbonyl, a homoleptic complex.
3 Marks Questions and Answers
Question 1.

Explain Werner's postulate using $\mathrm{CO} \mathrm{Cl}_3 \cdot 6 \mathrm{NH}_3$.
Answer:

Question 2.
What is the oxidation state in coordination compound? Explain with example.
Answer:
The oxidation state of a central metal atom in a coordination entity is defined as the charge it would bear if all the ligands were removed along with the electron pairs that were shared with the central atom. In naming a complex, it is represented by a Roman numeral. For e.g., in coordination entity $\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{4-}$ the oxidation state of iron is represented as (II). $\operatorname{In}\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{4-}$, let the oxidation number of iron is $\mathrm{x}$
The net charge $=-4$
$
\begin{aligned}
& x+6(-1)=-4 \\
& x-6=-4 \\
& x=6-4 \\
& =+2
\end{aligned}
$
So, iron oxidation state (II).
Question 3.
Explain the types of complexes based on the charge on the complex.
Answer:
The coordination compounds can be classified into the following types based on the net charge of the complex ion. A coordination compound in which the complex ion
- carries a net positive charge is called a cationic complex.
Example $\left[\mathrm{Ag}\left(\mathrm{NH}_3\right)_2\right]^{+}$
- carries a net negative charge is called an anionic complex.
Example $\left[\mathrm{Ag}(\mathrm{CN})_2\right]^{-}$
- bears no net charge is called a neutral complex.
Example $\left[\mathrm{Ni}(\mathrm{CO})_4\right]$
Question 4.
What is meant by ligand? Explain their types with examples.
Answer:
The ligands are the atoms of groups of atoms bound to the central metal atom / ion. The atom in a ligand that is bound directly to the central metal atom is known as a donor atom.
Ligands are of 5 types
1. Cationic ligand - e.g., $\mathrm{NH}_2-\mathrm{NH}_3{ }^{+}$Hydrazinium
2. Anionic ligand - e.g., $\mathrm{Br}$ Bromido
3. Neutral ligand - e.g., $\mathrm{H}_2 \mathrm{O}$ Aqua
4. Mono dendate ligand - A ligand can be connected by one coordinate bond, e.g - F fluorido
5. Ambidendate ligand - A ligand can be connected by more than one coordinate mode.
- e.g., $-\mathrm{NCS}$ iso thio cyanato $(\mathrm{KN})$

$\circ-\mathrm{SCN}$ thio cyanato $(\mathrm{KS})$
Question 5.
Identify the following terms in the complex $\left[\mathrm{K}_4 \mathrm{Fe}(\mathrm{CN})_6\right]$
(i) Cation
(ii) Anion
(iii) ligands
(iv) central metal ion
(v) Oxidation state of metal
(vi) IUPAC name
Answer:

Question 6 .
Identify and write the following in the complex $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_4 \mathrm{Cl}_2\right] \mathrm{Cl}$
(i) Cation
(ii) Ligands
(iii) Name of the ligand
(iv) central metal
(v) Oxidation state of central metal
(vi) Anion
(vii) IUPAC name $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_4 \mathrm{Cl}_2\right] \mathrm{Cl}$
Answer:

Question 7.
Write the following in the complex $\left[\mathrm{Cr}(\mathrm{en})_3\right]\left[\mathrm{Cr}_6\right]$
1. Type of complex
2. Ligands
3. central metal
4. Oxidation state of central metal
5. IUPAC name
Answer:

Question 8 .
Write the IUPAC names of the following complexes.
1. $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_5 \mathrm{CN}\right]\left[\mathrm{CO}\left(\mathrm{NH}_3\right)(\mathrm{CN})_5\right]$
2. $\left[\mathrm{Pt}(\mathrm{Py})_4\right]\left[\mathrm{Pt} \mathrm{Cl}_4\right]$
3. $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_4 \mathrm{Cl}_2\right]_3\left[\mathrm{Cr}(\mathrm{CN})_6\right]$
Answer:
1. $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_5 \mathrm{CN}\right]\left[\mathrm{CO}\left(\mathrm{NH}_3\right)(\mathrm{CN})_5\right]$
Penta ammine cyanido - $\mathrm{K}$ C Cobalt (III) ammine penta cyanido - $\mathrm{K}$ C Cobaltate (III)
2. $\left[\mathrm{Pt}(\mathrm{Py})_4\right]\left[\mathrm{Pt} \mathrm{Cl}_4\right]$
Tetra pyridine platinum (II) tetrachlorido platinate (II)
3. $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_4 \mathrm{Cl}_2\right]_3\left[\mathrm{Cr}(\mathrm{CN})_6\right]$
Tetraammine dichlorido cobalt (III) hexacyanido $\mathrm{KC}$ chromate (III)
Question 9.
Explain coordination isomerism with suitable example.
Answer:
1. Coordination isomerism arises in the coordination compounds having both the cation and anion as complex ions. The interchange of one or more ligands between cationic and the anionic coordination entities result in different isomers.
2. Fox e.g., in the coordination compound, $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_6\right]\left[\mathrm{Cr}(\mathrm{CN})_6\right]$, the ligands ammonia and cyanide were bound respectively to cobalt and chromium while in its coordination isomer $\left[\mathrm{Cr}\left(\mathrm{NH}_3\right)_6\right]\left[\mathrm{CO}(\mathrm{CN})_6\right]$, they are reversed.

Question 10 .
Explain ionisation isomerism with suitable example.
Answer:
1. Ionisation isomerism arises when an ionisable counter ion (simple ion) itself can act as a ligand.
2. The exchange of such counter ions with one or more ligands in the coordinatioin entity will result in ionisation isomers. These isomers will give different ions in solution.
3. For example, consider the coordination compound $\left[\mathrm{Pt}(\mathrm{en})_2 \mathrm{Cl}_2\right] \mathrm{Br}_2$. In this compound, both $\mathrm{Br}$ and $\mathrm{CP}$ have the ability to act as a ligand and the exchange of these two ions result in a different isomer $\left[\mathrm{Pt}(\mathrm{en})^{-}, \mathrm{Br}_2\right] \mathrm{Cl}$,. $\mathrm{In}$ solution, the first compound $\mathrm{Br}^{-}$ions while the later gives $\mathrm{CP}$ ions and hence these compounds are called ionisation isomers.

Question 11.
Explain the type of isomers possible for the formula $\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right] \mathrm{Cl}_3$ with their colour.
Answer:
1. $\mathrm{Cr} \mathrm{Cl}_3 6 \mathrm{H}_2 \mathrm{O}$ has three hydrate isomers.
2. $\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right] \mathrm{Cl}_3-\mathrm{A}$ violet colour compound and gives 3 chloride ions in solution.
3. $\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_5\right] \mathrm{Cl}_2 \mathrm{H}_2 \mathrm{O}-\mathrm{A}$ pale green colour compound and gives 2 chloride ions in solution.
4. $\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_4 \mathrm{Cl}_2\right] \mathrm{Cl} \cdot 2 \mathrm{H}_2 \mathrm{O}-\mathrm{A}$ dark green colour compound and gives one chloride ion in solution.
Question 12.
Mention the coordination number, hybridisation and geometry of the following compounds.
(i) $[\mathrm{Cu} \mathrm{Cl}]^{-}$
(ii) $\left[\mathrm{Hg} \mathrm{I} \mathrm{I}_3\right]^{-}$
(iii) $\mathrm{Ni}(\mathrm{CO})_4$
Answer:

Question 13.
Metion the coordination number, hybridisation and geometry of the following compounds.
(i) $\left[\mathrm{Ni}(\mathrm{CN})_4\right]^{2-}$
(ii) $\left[\mathrm{Fe}(\mathrm{CO})_5\right]$
(iii) $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_6\right]^{3+}$
Answer:

Question 14.
How is spectrochemical series is used to identify the type of ligands?
Answer:
1. $\mathrm{I}^{-}<\mathrm{Br}^{-}<\mathrm{SCN}^{-}<\mathrm{Cl}<\mathrm{S}^{2-}<\mathrm{F}^{-}<\mathrm{OH}^{-} \approx$ urea $<\mathrm{OH}^{2-}<\mathrm{H}_2 \mathrm{O}<\mathrm{NCS}^{-}<\mathrm{EDTA}^{4-}<\mathrm{NH}_3<\mathrm{en}^2<\mathrm{NO}_2^{-}<\mathrm{CN}^{-}$ $\mathrm{CO}$ The above series is known as spectrochemical series.
2. The ligands present on the right side of the series such as carbonyl causes relatively larger crystal field splitting and are called strong ligands (or) strong field ligands.
3. The ligands on the left side are called weak field ligands and causes relatively smaller crystal field splitting.
Question 15 .
Most of the transition metal complexes are coloured. Justify this statement.
Answer:
1. A substance exhibits colour when it absorbs the light of a particular wave length in the visible region and transmit the rest of the visible light.
2. When this transmitted light enters our eye, our brain recognises its colour. The colour of the transmitted light is given by the complementary colour of the absorbed light.
3. For e.g., the hydrate copper (II) ion is blue in colour as it absorbs orange light and transmit its complementary colour, blue.
Question 16.
Using crystal field theory, explain the colour of the coordination compound.
Answer:
1. The ligand field causes the splitting of $d$ orbitals of the central metal atom into two sets $\left(t_2 \mathrm{~g}\right.$ and eg).
2. When the white light falls on the complex ion, the central metal ion absorbs visible light corresponding to the crystal field splitting energy and transmits rest of the light which is responsible for the colour of the complex.
3. This absorption causes excitation of $\mathrm{d}$-electrons of the central metal ion from the lower energy $\mathrm{t}_{2 \mathrm{~g}}$ level to the higher energy eg level which is known as $\mathrm{d}-\mathrm{d}$ transition.
Question 17.
$\left.\mathrm{Ti}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+}$ is purple in colour. Prove this statement.
Answer:
1. In $\left[\mathrm{Ti}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+}$, the central metal ion is $\mathrm{Ti}^{3+}$ which has $\mathrm{d}^1$ configuration. This single electron occupies one of the $t_{2 g}$ orbitals in the octahedral aqua ligand field.
2. When white light falls on this complex, the d electron absorbs light and promotes itself to eg level.

3. The spectral data show the absorption maximum is at $20000 \mathrm{~mol}^{-1}$ corresponding to the crystal field splitting energy $\left(\Delta_0\right) 239.7 \mathrm{~kJ} \mathrm{~mol}^{-1}$. The transmitted colour associated with this absorption is purple and hence the complex appears in purple in colour.
Question 18.
$\mathrm{Cu}^{+}, \mathrm{Zn}^{2+}, \mathrm{Sc}^{3+}, \mathrm{Ti}^{4+}$ are colourless. Prove this statement.
Answer:
1. $\mathrm{Cu}^{+}, \mathrm{Zn}^{2+}$ have $\mathrm{d}^{10}$ configuration and $\mathrm{SC}^{3+}, \mathrm{Ti}^{4+}$ have $\mathrm{d}^1$ configuration.
2. $d-d$ transition is not possible in the above complexes. So they are colourless.
Question 19.
Explain about the bonding in metal carbonyls.
Answer:
1. In metal carbonyls, the bond between metal atom and the carbonyl ligand consists of two components. The first component is an electron pair donation from the carbon atom of the carbonyl ligand into a vacant $d$ - orbital of central metal atom. This electron pair donation forms $\mathrm{M}$ gbond $\mathrm{CO}$ and sigma bond.
2. This a bond formation increases the electron density in metal $\mathrm{d}$ orbitals and makes the metal electron rich.
3. In order to compensate for this increased electron density, a filled metal $d$-orbital interacts with the empty $n$ orbital on the carbonyl ligand and transfers the added electron density back to the ligand. This second component is called $n$ back bonding.
4. Thus in metal, carbonyl, electron density moves from ligand to metal through o bonding and from metal to ligand through $\mathrm{Pi}$ bonding, this synergic effect accounts for strong $\mathrm{M} \leftarrow \mathrm{CO}$ bond in metal carbonyls.
Question 20.
Explain the medicinal applications of coordination compounds?
Answer:
1. $\mathrm{Ca}$-EDTA chelate is used in the treatment of lead and radioactive poisoning. This is for removing lead and radioactive metal ions from the body.
2. Cis - platin is used as an anti tumor drug in cancer treatment
5 Marks Questions and Answers
Question 1.

Write the IUPAC name of the following complexes.
1. $\left[\mathrm{Ag}\left(\mathrm{NH}_3\right)_2\right] \mathrm{Cl}$
2. $\left[\mathrm{CO}(\mathrm{en})_2 \mathrm{Cl}_2\right] \mathrm{CI}$
3. $\left[\mathrm{Cu}\left(\mathrm{NH}_3\right)_4\right] \mathrm{SO}_4$
4. $\left[\mathrm{CO}\left(\mathrm{CO}_3\right)\left(\mathrm{NH}_3\right)_4\right] \mathrm{Cl}$
5. $\left[\mathrm{Cr}\left(\mathrm{NH}_3\right)_3\left(\mathrm{H}_2 \mathrm{O}\right)_3\right] \mathrm{Cl}_3$
Answer:
1. $\left[\mathrm{Ag}\left(\mathrm{NH}_3\right)_2\right] \mathrm{Cl}$ - Diammine Silver (I) Chloride
2. $\left[\mathrm{CO}\right.$ (en) $\left.{ }_2 \mathrm{Cl}_2\right] \mathrm{CI}$ - Dichloridobis (ethane -1, 2-diamine) Cobalt (III) chloride.
3. $\left[\mathrm{Cu}\left(\mathrm{NH}_3\right)_4\right] \mathrm{SO}_4-$ Tetraammine copper (II) Sulphate
4. $\left[\mathrm{CO}\left(\mathrm{CO}_3\right)\left(\mathrm{NH}_3\right)_4\right] \mathrm{Cl}$ - Tetrammine carbanato cobalt (III) chloride
5. $\left[\mathrm{Cr}\left(\mathrm{NH}_3\right)_3\left(\mathrm{H}_2 \mathrm{O}\right)_3\right] \mathrm{Cl}_3$ - Triammine tri aqua chromium (III) chloride
Question 2.
Explain about the geometrical isomerism in complexes having coordination number 4 .
Answer:
1. Geometrical isomerism exists in heteroleptic complexes due to different possible three diamensional spatial arrangements of the ligands around the central metal atom. This type of isomerism exist in square planar tetrahedral complexes.
2. In square planar complexes of the form $\left[\mathrm{MA}_2 \mathrm{~B}_2\right]^{\mathrm{n \pm}}$ and $\left[\mathrm{MA}_2 \mathrm{BC}\right]^{\mathrm{N+}}$ where $\mathrm{A}, \mathrm{B}$ and $\mathrm{C}$ are monodentate ligands and $\mathrm{M}$ is the central metal ion / atom.
3. Similar groups (A or B) present either on same side or on the opposite side of the central metal atom (M) give rise to two different geometrial isomers and they are called cis and trans isomers respectively.
4. The square planar complex of the type $\left[\mathrm{M}(\mathrm{XY})_2\right]^{\mathrm{n \pm}}$ where $\mathrm{XY}$ is a bidentate ligand with two different coordinating atom also shows cis-trans isomerism.
5. Square planar complex of the form $[M A B C D]^{\mathrm{n} \pm}$ also shows cis - trans isomerism. In this case, by considering any one of the ligands $[A, B, C, D]$ as a reference, the rest of the ligands can be arranged in three different ways leading to three geometrical isomers.

Question 3
Explain about the geometrical isomerism of octahedral complexes with suitable example.
Answer:
1. Octahedral complexes of the type $\left[M_2 B_2\right]^{\mathrm{n} \pm},\left[M(x x)_2 B_2\right]^{\mathrm{n \pm}}$ shows cis-trans isomerism. Hence $A$ and $B$ are monodentate ligands and $\mathrm{xx}$ is bidentate ligand with two same kind of donor atoms. In the octahedral
complex, the position of ligands is indicated by the. following numbering scheme.

2. The positions $(1,2)(1,3)(1,4)(1,5),(2,3)(2,5)(2,6),(3,4)(3,6)(4,5)(4,6)$ and $(5,6)$ are identical and if two similar groups are present in any one of these positions, the isomer is referred as a cis-isomer.
3. Similarly positions $(1,6),(2,4)$ and $(3,5)$ are identical and if similar groups (or) ligands are present in these positions it is referred as a trans - isomer.
4. Octahedral complex of the type $\left[\mathrm{MA}_3 \mathrm{~B}_3\right]^{\mathrm{n} \pm}$ also shows geometrical isomerism. If the three similar ligands (A) are present in the comers of one triangular face of the octahedron and the other 3 ligands (B) are present in the opposing triangular face, then the isomer is referred as a facial isomer (fac isomer).
5. If the three similar ligands are present around the meridian which is an imaginary semicircle from one apex of the octahedral to the opposite apex, the isomer is called a meridional isomer (mer is omer). This is called a meridional because each set of ligands can be regarded as lying on a meridian of an octahedran.
Question 4.
Describe about the postulate of VB theory (or) Valence bond theory.
Answer:
1. The ligand $\rightarrow$ metal bond in a coordination complex is covalent in nature. It is formed by the sharing of electrons between the central metal atom and electron donor ligand.
2. Each ligand should have atleast one filled orbital containing a lone pair of electrons.
3. In order to accommodate the electron pairs donated by the ligands, the central metal ion present in a complex provides required number of vacant orbitals.
4. These vacant orbitals of central metal atoms undergo hybridisation, the process of mixing of atomic orbitals of comparable energy to form equal number of new orbitals called hybridised orbitals with same energy.
5. The vacant hybridised orbitals of the central metal ion, linearly overlap with filled orbitals of the ligands to form coordinate covalent sigma bonds between the metal and the ligand.
6. The hybridised orbitals are directional and their orientation in space gives a definite geometry to the complex ion

7. In the octahedral complexes, if the (n-1)d orbitals are involved in hybridisation they are called inner orbital complexes or low spin complexes (or) spin paired complexes. If the nd orbitals are involved in hybridisation, such complexes are called outer orbital complexes (or) high spin (or) spin free complexes. Here " $n$ " represents the principal quantum number of the outermost shell.
8. The complexes containing a central metal atom with unpaired electron (s) are paramagnetic. If all the electrons are paired, then the complexes will be diamagnetic.
9. Ligands such as $\mathrm{CO}, \mathrm{CN}^{-}$, en and $\mathrm{NH}_3$ present in the complexes cause pairing of electrons present in the central metal atom. Such ligands are called strong field ligands.
10. Greater the overlapping between, the ligand orbitals and the hybridised metal orbital, greater is the bond strength.
Question 5.
Explain the hybridisation, magnetic property, geometry, magnetic moment of $\left[\mathrm{Ni}(\mathrm{CO})_4\right] \mathrm{Using}$ valence bond theory

Answer:

Question 6.
Explain the hybridisation, geometry, magnetic property and magnetic moment of $\left[\mathrm{Ni}(\mathrm{CN})_4\right]^{2-}$ using valence bond theory.
Answer:

Question 7.
Using VB theory, explain the type of hybridisation, geometry, magnetic property and magnetic moment of $[\mathrm{Fe}$ $\left.(\mathrm{CN})_6\right]^{3-}$.
Answer:

Question 8.
Explain the hybridisation, geometry, magnetic property and magnetic moment $\left[\mathrm{CO} \mathrm{F}_6\right]^{3-}$
Answer:

Question 9.
Explain about crystal field theory.
Answer:
1. Crystal field theory assumes that the bond between the ligand and the central metal atom is purely ionic, i.e., the bond is framed due to the electrostatic attraction between the electron rich ligand and electron deficient metal.
2. In the coordination compounds, the central metal atom/ion and the ligands are considered as point charges (or) electric dipoles.
3. cording to crystal field theory, the complex formation is considered as the following series of hypothetical steps.
Step 2:
The ligands are approaching the metal atom in actual bond directions. Consider an octahedral field, in which the central metal ion is located at the origin and six ligands are coming from the $+x,-x,+y,-y,+z$ and $-z$ directions. The orbitals lying along the axes $\mathrm{dx}^2-\mathrm{y}^2$ and $\mathrm{dz}^2$ orbitals will experience strong repulsion and raise in energy to a greater extent than the orbitals with lobes directed between the axes (dxy, dyz and dxz). Thus the degenerate $d$ orbitals now split into two sets and the process is called crystal field splitting.
Step 3:
Upto this point the complex formation would not be favoured. However when the ligands approach further, there will be an attraction between the negatively charged electron and the positively charged metal ion that results in a net decrease in energy. This decrease in energy is the driving force for the complex formation.
Question 10 .
Describe about the crystal field splitting in tetrahedral complex.
Answer:
1. Consider a cube in which the central metal atom is placed at its centre (i.e., origin of the coordinate axis). The four ligands approach the central metal atom along the direction of the leading diagonals from the alternate comers of the cube.
2. In this field, the $\mathrm{t}_{2 \mathrm{~g}}$ orbitals $\left(\mathrm{d}_{\mathrm{xy}}, \mathrm{d}_{\mathrm{yz}}\right.$ and $\mathrm{d}_{\mathrm{zx}}$ ) are pointing close to the direction in which ligands are approaching than the 'eg' orbitals. $\left(\mathrm{dx}^2-\mathrm{y}^2\right.$ and $\mathrm{dz} \mathrm{z}^2$ ). As a result, the energy of $\mathrm{t}_{2 \mathrm{~g}}$ orbitals increases by $2 / 5 \Delta t$ and that of ' $\mathrm{e}$ ' orbitals decreases by $3 / 5 \Delta \mathrm{t}$ as shown in the figure. This splitting is inverted when compared to octahedral field.

Question 11.
How would you calculate crystal field stabilization energy (CBSE) for $\left[\mathrm{Fe}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{3+} . \mathrm{Complex}:\left[\mathrm{Fe}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{3+}$
Answer:

Question 12 .
How would you measure $\mathrm{CBSE}$ for $\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{3-}$.
Answer:

Question 13.
Explain about the classification of metal carbonyls with suitable examples. Classification:
Answer:
1. based on the number of metal atoms present. Depending upon the number of metal atoms present in a metalic carbonyl, they are classified as follows.
(a) Mono nuclear carbonyls. These compounds contain only one metal atom and have simple structures. For e.g.,
$\left[\mathrm{Ni}(\mathrm{CO})_4\right]$ Nickel tetra carbonyl is tetrahedral, $\left[\mathrm{Fe}(\mathrm{CO})_5\right]$ Iron pentacarbonyl is trigonalbipyramidal. $[\mathrm{Cr}$ $(\mathrm{CO})_6$ ] Chromium hexacarbonyl is octahedral.
(b) Poly nuclear carbonyls Metallic carbonyls containing two or more metal atoms are called poly nuclear carbonyls. Poly nuclear metal carbonyls may be -
Homonuclear - $\left(\left[\mathrm{CO}_2(\mathrm{CO})_6\right],\left[\mathrm{Mn}_2(\mathrm{CO})_{10}\right],\left[\mathrm{Fe}_3(\mathrm{CO})_{12}\right]\right)$
Fletero nuclear - $\left(\left[\mathrm{MnCO}(\mathrm{CO})_9\right],\left[\mathrm{MnRe}(\mathrm{CO})_{10}\right]\right)$


2. based on structure. The structures of binuclear metal carbonyls involve either metal-metal bonds or bridging Co groups or both. The carbonyl ligands that are attached to only one metal atom are referred to as terminal carbonyl groups, whereas those attached to two metal atoms simultaneously are called bridging carbonyls.
Depending upon the structures of metal metal carbonyls they are classified as follows:

(a) Non - bridged metal carbonyls.
Example:- $\left[\mathrm{Ni}(\mathrm{CO})_4\right]$
These metal carbonyls do not contain any bridging carbonyl lieands. Thev mav be of two tves. Non- bridged metal carbonyls which contain terminal carbonyls as well as Metal- Metal bonds. For examples, The structure of $\mathrm{Mn}_2(\mathrm{CO})_{10}$. Contains one metal - metal bond, so the formula is more correctly represented as (CO) ${ }_5 \mathrm{Mn}-$ $\mathrm{Mn}(\mathrm{CO})_5$
(b) Bridged carbonyls:
These metal carbonyl contain one or more bridging carbonyl ligands along with terminal carbonyl ligands and one or more metal - metal bonds For Example: $\mathrm{Fe}(\mathrm{CO})_9$ Di-iron ennea carbonyl molecule consists of three CO ligands, six terminal $\mathrm{CO}$ groups and single $\mathrm{Fe}-\mathrm{Fe} \mathrm{A}$ bond formed by weak coupling of the unpaired electrons present in two $3 \mathrm{~d}$ orbitals of $2 \mathrm{Fe}$ atoms. The bond represented by dotted line is called fractional single bond.

Question 14.
Explain about the importance and application of coordination complexes.
Answer:
1. Phthalo blue - a bright blue pigment is a complex of copper (II) ion and it is used in printing ink and packaging industry.
2. Purification of Nickel by Mond's process involves formation of $\left[\mathrm{Ni}(\mathrm{CO})_4\right]$ which yields $99.5 \%$ pure on decomposition.
3. EDTA is used as a chelating ligand for the separation of lanthanides, in softening of hard water and also in removing lead poisoning.
4. Coordination complexes are used in the extraction of silver and gold from their ores by forming soluble cyano complex. These cyano complexes are reduced by zinc to yield metals. This process is called Mac - Arthur Forrest cyanide process.
5. Some metal ions are estimated more accurately by complex formation. For eg., $\mathrm{Ni}^{2+}$ present in Nickel chloride solution is estimated accurately forming an insoluble complex called [Ni (DMG) ${ }_2$ ],
6. Many of the complexes are used as catalyst in organic and inorganic reactions. For e.g.,
- Wilkinson's Catalyst - $\left[\left(\mathrm{PPh}_3\right)_3 \mathrm{Rh} \mathrm{Cl}\right]$ is used for hydrogenation of alkenes.
- Ziegler - Natta Catalyst $\left[\mathrm{TiCl}_4+\mathrm{Al}\left(\mathrm{C}_2 \mathrm{H}_5\right)_3\right]$ is used in the polymerisation of ethene.
7. In photography, when the developed film is washed with sodium thio sulphate solution (hypo), the negative film gets fixed. Undecomposed $\mathrm{AgBr}$ forms a soluble complex called sodium dithio sulphate argentate (I) which can be removed easily by washing the film with water.
$\mathrm{AgBr}+2 \mathrm{Na}_2 \mathrm{~S}_2 \mathrm{O}_3 \rightarrow \mathrm{Na}_3\left[\mathrm{Ag}\left(\mathrm{S}_2 \mathrm{O}_3\right)_2\right]+2 \mathrm{NaBr}$
Question 15 .
Write the formulae for the following coordination compounds:
Answer:
1. Tetraamminediaquacobalt (III) chloride.
2. Potassium tetracyanonickelate (II).
3. Tris ( ethane $-1,2$ - diamine ) chromium (III) chloride.
4. Amminebromidochloridonitrito $-\mathrm{N}-$ platinate (II).
5. Dichlorobis(ethane - 1,2-diamine ) platinum (IV) nitrate.
6. Iron (III) hexacyanoferrate (II)
Answer:

1. $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_4\left(\mathrm{H}_2 \mathrm{O}\right)_2\right] \mathrm{Cl}_3$
2. $\mathrm{K}_2\left[\mathrm{Ni}(\mathrm{CN})_4\right]$
3. $\left[\mathrm{Cr}(\mathrm{en})_3\right] \mathrm{Cl}_3$
4. $\left[\mathrm{Pt}\left(\mathrm{NH}_3\right) \mathrm{BrCl}\left(\mathrm{NO}_2\right)\right]^{-}$
5. $\left[\mathrm{PtCl}_2(\mathrm{en})_2\right]\left(\mathrm{NO}_3\right)_2$
6. $\mathrm{Fe}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right]_3$
Question 16.
Write the IUPAC names of the following:
1. $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_6\right] \mathrm{Cl}_3$
2. $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_5 \mathrm{Cl}\right] \mathrm{Cl}_2$
3. $\mathrm{K}_3\left[\mathrm{Fe}(\mathrm{CN})_6\right]$
4. $\mathrm{K}_3\left[\mathrm{Fe}\left(\mathrm{C}_2 \mathrm{O}_4\right)_3\right]$
5. $\mathrm{K}_2\left[\mathrm{PdCl}_4\right]$
6. $\left[\mathrm{Pt}\left(\mathrm{NH}_3\right)_2 \mathrm{Cl}\left(\mathrm{NH}_2 \mathrm{CH}_3\right)\right] \mathrm{Cl}$
Answer:
1. Hexaamine cobalt (III) chloride
2. Pentaamine chloridocobalt (III) chloride
3. Potassium hexacyanoferrate (III)
4. Potassium trioxalatoferrate (III)
5. Potassium tetrachlorido palladate (II)
6. Diamminechlorido (methylamine) platinum (II) chloride
Question 17.
Indicate the types of isomerism exhibited by the following complexes and draw the structures for these isomers:
1. $\mathrm{K}\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_2\left(\mathrm{C}_2 \mathrm{O}_4\right)_2\right]$
2. $\left[\mathrm{CO}(\mathrm{NH})_3 \mathrm{Cl}\right] \mathrm{Cl}_2$
3. $\mathrm{K}_3\left[\mathrm{Fe}(\mathrm{CN})_6\right]$
4. $\mathrm{K}_3\left[\mathrm{Fe}\left(\mathrm{C}_2 \mathrm{O}_4\right)_3\right]$
5. $\mathrm{K}_2\left[\mathrm{PdCl}_4\right]$
6. $\left[\operatorname{Pt}\left(\mathrm{NH}_3\right)_2 \mathrm{Cl}\left(\mathrm{NH}_2 \mathrm{CH}_3\right)\right] \mathrm{Cl}$
Answer:
1. Both geometrical (cis, trans) and optical isomer for cis - form.

2. Two optical isomers can exist.

3. Linkage isomers $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_5 \mathrm{ONO}\right]\left(\mathrm{NO}_3\right)_2$ and $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_5 \mathrm{NO}_2\right]\left(\mathrm{NO}_3\right)_2$
4. Geometrical isomerism.


Question 18.
Give evidence that $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_5 \mathrm{Cl}\right] \mathrm{SO}_4$ and $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_5 \mathrm{SO}_4\right] \mathrm{Cl}$ are ionisation isomers.
Answer:
When they are dissolved in water, they will give different ions in the solution which can be tested by adding $\mathrm{AgNO}_3$ solution and $\mathrm{BaCl}_2$ solution. When $\mathrm{Cl}$ ions are the counter ions, a white precipitate will be obtained with
$\mathrm{AgNO}_3$ solution. If $\mathrm{SO}_4^{2-}$ ions are the counter ions, a white precipitate will be obtained with $\mathrm{BaCl}_2$ solution. $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_5 \mathrm{Cl}\right] \mathrm{SO}_4(\mathrm{aq})+\mathrm{BaCl}_2(\mathrm{aq}) \rightarrow \mathrm{BaSO}_4(\mathrm{~s}) \downarrow$
ppt
$\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_5 \mathrm{Cl}\right] \mathrm{SO}_4(\mathrm{aq})+\mathrm{AgNO}_3 \rightarrow$ No reaction
$\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_5 \mathrm{SO}_4\right] \mathrm{Cl}(\mathrm{aq})+\mathrm{BaCl}_2(\mathrm{aq}) \rightarrow$ No reaction
$\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_5 \mathrm{SO}_4\right] \mathrm{Cl}(\mathrm{aq})+\mathrm{AgNO}_3(\mathrm{aq}) \rightarrow \mathrm{AgCl}(\mathrm{s}) \downarrow$
ppt

Question 19.
Explain on the basis of valence bond theory that $\left[\mathrm{NI}(\mathrm{CN})_4\right]^{2-}$ ion with square planar structure is diamagnetic and the $\left[\mathrm{NI}(\mathrm{CN})_4\right]^{2-}$ ion with tetrahedral geometry is paramagnetic.
Answer:
Nickel in $\left[\mathrm{NI}(\mathrm{CN})_4\right]^{2-}$ is in the +2 oxidation state, i.e. nickel is present as $\mathrm{Ni}^{2+}$ ion. dsp ${ }^2-$ hybrid orbitals

$\mathrm{CN}^{-} \text {is a strong ligand as it approaches the metal ion, So the electrons should getd paired up. }$

Hence the hybridisation is $\mathrm{sp}^3$, and it is para - magnetic.
Question 20.
$\left[\mathrm{NI}(\mathrm{CN})_4\right]^{2-}$ is paramagnetic while $\left[\mathrm{Ni}(\mathrm{CO})_4\right]^{3-}$ is diamagnetic though both are tetrahedral. Why?
Answer:
In $\left[\mathrm{NI}(\mathrm{CN})_4\right]^{2-}, \mathrm{Ni}$ is in +2 oxidation state with electronic configuration $=3 \mathrm{~d}^8 4 \mathrm{~s}^{\circ}$.
$\mathrm{Cl}^{-}$is a weak ligand. It cannot pair up the electrons in $3 \mathrm{~d}$ orbitals. Hence, it is paramagnetic. $\mathrm{In}\left[\mathrm{Ni}(\mathrm{CO})_4\right], \mathrm{Ni}$ is in zero oxidation state and its configuration is $-3 \mathrm{~d}^8 4 \mathrm{~S}^2$. In the presence of $\mathrm{CO}$ ligand the 4 s electrons shift to $3 \mathrm{~d}$ orbital to pair up the $3 \mathrm{~d}$ electrons. Thus, there is no unpaired electron present. Hence it is diamagnetic.
Question 21.
$\left[\mathrm{Fe}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{3+}$ is strongly paramagnetic whereas $\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{3-}$ is weakly paramagnetic. Explain.
Answer:
In both the complexes, $\mathrm{Fe}$ is in +3 oxidation state with the configuration $3 \mathrm{~d}^5 . \mathrm{CN}^{-}$is a strong field ligand. In its presence, $3 \mathrm{~d}$ electrons pair up leaving only one unpaired electron. The hybridisation is $\mathrm{d}^2 \mathrm{sp}^3$ forming inner orbital complex. $\mathrm{H}_2 \mathrm{O}$ is a weak ligand. In its presence $3 \mathrm{~d}$ electrons do not pair up. The hybridisation is $\mathrm{sp}^3 \mathrm{~d}^2$ forming an outer orbital complex containing five unpaired electrons, hence it is strongly paramagnetic.
Question 22.
Explain $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_6\right]^{3+}$ is an inner orbital complex whereas $\left[\mathrm{Ni}\left(\mathrm{NH}_3\right)_6\right]^{2+}$ is an outer orbital complex.
Answer:
In $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_6\right]^{3+}$, oxidation state of $\mathrm{CO}=+3$ Electronic configuration $=3 \mathrm{~d}^6$
In presence of $\mathrm{NH}_3, 3 \mathrm{~d}$ electrons pair up leaving two $\mathrm{d}$-orbitais empty. Hence, the hybridisation is $\mathrm{d}^2 \mathrm{p}^2$ forming an inner orbital complex. In $\left[\mathrm{Ni}\left(\mathrm{NH}_3\right)_6\right]^{2+}$.

Oxidation state $=+2$, Electronic Configuration $=3 \mathrm{~d}^8$. In the presence of $\mathrm{NH}_3, 3 \mathrm{~d}$ electrons do not pair up. The hybridisation involved is, $s^3 \mathrm{~d}^2$ and it forms an outer orbital complex.
Question 23.
Predict the number of unpaired electrons in the square planar $\left[\mathrm{Pt}(\mathrm{CN})_4\right]^{2-}$ ion.
Answer:
Electronic Configuration of $\mathrm{Pt}=5 \mathrm{~d}^9 6 \mathrm{~s}^1$

For square planar shape, hybridisation $=\mathrm{dsp}^2$
Hence, the unpaired electron in $5 \mathrm{~d}$ - orbital pair up to make one $d$-orbital empty for $\mathrm{dsp}^2$ hybridisation. Thus, there is no unpaired electron.
Question 24.
$\left[\mathrm{Cr}\left(\mathrm{NH}_3\right)_6\right]^{3+}$ is paramagnetic while $\left[\mathrm{Ni}(\mathrm{CN})_4\right]^2$ is diamagnetic. Explain why?
Answer:
$\mathrm{Cr}(24):[\mathrm{Ar}] 4 \mathrm{~s}^1 3 \mathrm{~d}^5$
$\mathrm{Cr}^{3+}(24):[\mathrm{Ar}] 4 \mathrm{~s}^{\circ} 3 \mathrm{~d}^3$

It is paramagnetic due to the presence of unpaired electrons.


It has a square planar structure, and it is diamagnetic due to the absence of unpaired electrons.

Question 25 .
Write down the IUPAC name for each of the following complexes and indicate the oxidation state, electronic configuration and coordination number. Also give stereo - chemistry and magnetic moment of the complex.
1. $\mathrm{K}\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_2\left(\mathrm{C}_2 \mathrm{O}_4\right)_2\right] \cdot 3 \mathrm{H}_2 \mathrm{O}$
2. $\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_5 \mathrm{Cl} \mathrm{Cl}_2\right.$
3. $\mathrm{CrCl}_3(\mathrm{py})_3$
4. $\mathrm{Cs}\left[\mathrm{FeCl}_4\right]$
5. $\mathrm{K}_4\left[\operatorname{Min}(\mathrm{CN})_6\right]$
Answer:
1. Potassium diaquabis (oxalato) chromate (III) trihydrate.
Cordination no. $=6$
Shape $=$ Octahedral
Oxidation state of $\mathrm{Cr}=\mathrm{x}+0+2(-2)=-1$
(or)
$x-4=-1$
(or)
$\mathrm{x}=+3$
Electronic configuration of $\mathrm{Cr}^{3+}=3 \mathrm{~d}^3=\mathrm{t}_{2 \mathrm{~g}}{ }^3 \mathrm{e}_{\mathrm{g}}{ }^0$
No. of unpaired electrons (n) $=3$
Magnetic moment $(\mu)=g \sqrt{n(n+2)}=g \sqrt{3(5)}=g \sqrt{15} \mathrm{BM}=3.87 \mathrm{BM}$
2. Pentaamminechloro cobalt (III) chloride Cordination no. of $\mathrm{CO}=6$
Shape $=$ Octahedral Oxidation state of $\mathrm{CO}=\mathrm{x}+0-1=+2$
(or)
$\mathrm{x}=+3$
Electronic configuration of $\mathrm{CO}^{3+}=3 \mathrm{~d}^6=\mathrm{t}_{2 \mathrm{~g}}{ }^6 \mathrm{eg}^0$
$\mathrm{n}=0$
Magnetic moment (p) $=0$
3. Trichlorotripyridine chromium (III), Cordination no, of $\mathrm{Cr}=6$
Shape $=$ Octahedral Oxidation state of $\mathrm{Cr}_{\mathrm{r}}=\mathrm{x}-3+0=0$ $\mathrm{x}=+3$
Electronic configuration of $\mathrm{Cr}^{3+}=3 \mathrm{~d}^3=\mathrm{t}_{2 \mathrm{~g}}{ }^3 \mathrm{e}_{\mathrm{g}}{ }^0$ $\mathrm{n}=3$
Magnetic moment $(\mu)=g \sqrt{n(n+2)}=g \sqrt{3(5)}=g \sqrt{15} \mathrm{BM}=3.87 \mathrm{BM}$
4. Caesium tetrachloroferrate (III), Cordination no. of $\mathrm{Fe}=4$
Shape $=$ Tetrahedral Oxidation state of $\mathrm{Fe}=\mathrm{x}-4=-1$
$\mathrm{x}=+3$
Electronic configuration of $\mathrm{Fe}^{3+}=3 \mathrm{~d}^5=\mathrm{e}^2 \mathrm{t}_2{ }^3$
$\mathrm{n}=5$
$(\mu)=g \sqrt{5(5+2)}=g \sqrt{3(5)}=5.92 \mathrm{BM}$

5. Potassium hexacyanomanganate (II), Cordination no. of $\mathrm{Mn}=6$
Shape $=$ Octahedral Oxidation state of $\mathrm{Mn}=\mathrm{x}-6=-4$
$
\mathrm{x}=+2
$
Electronic configuration of $\mathrm{Mn}^{2+}=3 \mathrm{~d}^5=\mathrm{t}_{2 \mathrm{~g}}{ }^5 \mathrm{eg}^0$
$\mathrm{n}=1$
$(\mu)=g \sqrt{1(1+2)}=g \sqrt{3} \mathrm{BM}=1.73 \mathrm{BM}$
Question 26.
How to find out stability constant by stepwise method?
Answer:
When a free metal ion is in aqueous medium, it is surrounded by (coordinated with) water molecules. It is represented as $\left[\mathrm{MS}_6\right.$ ]. If ligands which are stronger than water are added to this metal salt solution, coordinated water molecules are replaced by strong ligands. Let us consider the formation of a metal complex $\mathrm{ML}_6$ in aqueous medium. (Charge on the metal ion is ignored) complex formation may occur in single step or step by step.
If ligands added to the metal ion in single step, then
$
\begin{aligned}
{\left[\mathrm{MS}_6\right]+6 \mathrm{~L} } & \equiv\left[\mathrm{ML}_6\right]+6 \mathrm{~S} \\
\beta_{\text {overall }} & =\frac{\left.1 \mathrm{ML}_6\right][\mathrm{S}]^6}{\left[\mathrm{MS}_6\right][\mathrm{L}]^6}
\end{aligned}
$
$\beta_{\text {overall }}$ is called as overall stability constant. As solvent is present in large excess, its concentration in the above equation can be ignored.
$
\therefore \quad \beta_{\text {overall }}=\frac{{ }^{[}\left[\mathrm{ML}_6\right][\mathrm{S}]^6}{\left[\mathrm{MS}_6\right][\mathrm{L}]^6}
$
If these six ligands are added to the metal ion one by one, then the formation of complex $\left[\mathrm{ML}_6\right]$ can be supposed to take place through six different steps as shown below. Generally step wise stability constants are represented by the symbol $\mathrm{k}$.

$
\begin{array}{ll}
{\left[\mathrm{MS}_6\right]+\mathrm{L} \rightleftharpoons\left[\mathrm{MS}_5 \mathrm{~L}\right]+\mathrm{S}} & \mathrm{k}_1=\frac{\left[\mathrm{MS}_5 \mathrm{~L}\right]}{\left[\mathrm{MS}_6\right][\mathrm{L}]} \\
{\left[\mathrm{MS}_5 \mathrm{~L}\right]+\mathrm{L} \rightleftharpoons\left[\mathrm{MS}_4 \mathrm{~L}_2\right]+\mathrm{S}} & \mathrm{k}_2=\frac{\left[\mathrm{MS}_4 \mathrm{~L}_2\right]}{\left[\mathrm{MS}_5\right][\mathrm{L}]} \\
{\left[\mathrm{MS}_4 \mathrm{~L}_2\right]+\mathrm{L} \rightleftharpoons\left[\mathrm{MS}_3 \mathrm{~L}_3\right]+\mathrm{S}} & \mathrm{k}_3=\frac{\left[\mathrm{MS}_3 \mathrm{~L}_3\right]}{\left[\mathrm{MS}_4 \mathrm{~L}_2\right][\mathrm{L}]} \\
{\left[\mathrm{MS}_3 \mathrm{~L}_3\right]+\mathrm{L} \rightleftharpoons\left[\mathrm{MS}_3 \mathrm{~L}_4\right]+\mathrm{S}} & \mathrm{k}_4=\frac{\left[\mathrm{MS}_2 \mathrm{~L}_4\right]}{\left[\mathrm{MS}_3 \mathrm{~L}_3\right][\mathrm{L}]} \\
{\left[\mathrm{MS}_2 \mathrm{~L}_4\right]+\mathrm{L} \rightleftharpoons\left[\mathrm{MSL}_5\right]+\mathrm{S}} & \mathrm{k}_5=\frac{\left[\mathrm{MSL}_5\right]}{\left[\mathrm{MS}_2 \mathrm{~L}_4\right][\mathrm{L}]} \\
{\left[\mathrm{MSL}_5\right]+\mathrm{L} \rightleftharpoons\left[\mathrm{ML}_6\right]+\mathrm{S}} & \mathrm{k}_6=\frac{\left[\mathrm{ML}_6\right]}{\left[\mathrm{MSL}_5\right][\mathrm{L}]}
\end{array}
$
Common Errors
1. Complex salt and double salt- Students get confused
2. Ligands name get confused
3. IUPAC names may be difficult.
Rectifications
1. Complex salt and double salt- Students get confused Complex salt have double brackets and double salt have no brackets.
2. Ligands name get confused Neutral ligand names are different. Negative ligand names ends with letter ' $\mathrm{O}$ '. Positive ligand names ends with 'ium'.
3. IUPAC names may be difficult. Cationic complex name starts with ligands name and Anionic complex names starts with first element whatever present.