Additional Questions - Chapter 14 Haloalkanes and Haloarenes 11th Chemistry Guide Samacheer Kalvi Solutions - SaraNextGen [2024-2025]

Updated By SaraNextGen

On April 24, 2024, 11:35 AM

Additional Questions Solved
I. Choose The Correct Answer.
Question 1.
Which of the following is an example for polyhalo compounds?
(a) Vnyl iodide
(b) Chiorobenzene
(c) Allyl chloride
(d) Chloroform
Answer:
(d) Chloroform
Question 2.
Which of the following is a secondary haloalkane?
(a) Bromoethane
(b) 2-Chioropropane
(c) 2-Jodo-2-methylpropane
(d) 1-Chloropropane
Answer:
(b) 2-Chioropropane
Question 3.
How many isomers are possible for the formula $\mathrm{C}_4 \mathrm{H}_9 \mathrm{Cl}$ ?
(a) 3
(b) 2
(c) 4
(d) 5
Answer:
(c) 4
Question 4.
How many isomers are possible for the formula $\mathrm{C}_5 \mathrm{H}_{11} \mathrm{Br}$ ?

(a) 11
(b) 8
(c) 4
(d) 5
Answer:
(b) 8
Question 5.
Which of the following is called Lucas reagent?
(a) Conc. $\mathrm{H}_2 \mathrm{SO}_4+$ Anhydrous $\mathrm{CuSO}_4$
(b) Conc. $\mathrm{HCl}+$ Anhydrous $\mathrm{ZnCl}_2$
(c) $\mathrm{Dil} \mathrm{HCl}+\mathrm{AlCl}_3$
(d) Conc. $\mathrm{HCl}+\mathrm{ConcHNO}_2$
Answer:
(b) Conc. $\mathrm{HCl}+$ Anhydrous $\mathrm{ZnCl}_2$

Question 6.
Which of the following mechanism is followed in the halogenation of alkanes in the presence of U-V light?
(a) Nucleophilic substitution
(b) Electrophilic addition
(c) Free radical substitution
(d) Elimination reaction
Answer:
(c) Free radical substitution
Question 7.
The reactivity of alcohols with haloacid is -
(a) $3^{\circ}>2^{\circ}>1^{\circ}$
(b) $1^{\circ}>2^{\circ}>3^{\circ}$
(c) $2^{\circ}>3^{\circ}>1^{\circ}$
(d) $3^{\circ}>1^{\circ}>2^{\circ}$
Answer:
(a) $3^{\circ}>2^{\circ}>1^{\circ}$
Question 8.
Which of the following reagent is not used to convert alcohol to haloalkane?
(a) $\mathrm{H}-\mathrm{X}$
(b) $\mathrm{PX}_5$
(c) $\mathrm{CCl}_4$
(d) $\mathrm{SOCl}_2$
Answer:
(c) $\mathrm{CCl}_4$

Question 9.
What is the name of the reaction in which bromoethane is converted to iodoethane by reacting with NaI in acetone?
(a) Hunsdicker reaction
(b) Dow's process
(c) Finkelstein reaction
(d) Swarts reaction
Answer:
(c) Finkeistein reaction
Question 10.
Identify the correct order of boiling point of haloalkanes?

Answer:

Question 11.
Which of the following pair functional groups represents ambident nucleophiles?
(a)-SH-&-OH
(b) $-\mathrm{CN}-\&-\mathrm{NO}_2$
(c) $-\mathrm{Br}-\&-\mathrm{Cl}$
(d)-O-&-CHO
Answer:
(b) $-\mathrm{CN} \& \mathrm{NO}_2$
Question 12.
Which one following mechanism will be followed when Tartiary butyl chloride is treated with alcoholic $\mathrm{KOH}$ ?
(a) $\mathrm{S}_{\mathrm{N}^1}$ mechanism
(b) $\mathrm{E}_1$ mechanism
(c) $\mathrm{S}_{\mathrm{N}^2}$ mechanism
(d) $\mathrm{E}_2$ mechanism
Answer:
(b) $\mathrm{E}_1$ mechanism
Question 13.
Which one of the following is used for producing pesticides?
(a) $\mathrm{CHI}_3$
(b) $\mathrm{CHCl}_3$
(c) $\mathrm{CCl}_3 \mathrm{NO}_2$
(d) $\mathrm{CCl}_4$
Answer:
(b) $\mathrm{CHCl}_3$
Question 14.
Which one of the following react with gringnard reagent followed by hydrolysis will yield primary alcohol?
(a) $\mathrm{CH}_3 \mathrm{CHO}$
(b) $\mathrm{HCHO}$
(c) $\mathrm{CH}_3 \mathrm{COCH}_3$
(d) $\mathrm{CO}_2$
Answer
(b) $\mathrm{HCHO}$
Question 15.
Which one of the following reacts with $\mathrm{CH}_3 \mathrm{MgI}$ followed by hydrolysis and gives isopropyl alcohol?
(a) $\mathrm{CH}_3 \mathrm{COCH}_3$
(b) $\mathrm{CH}_3 \mathrm{CHO}$
(c) $\mathrm{HCHO}$
(d) $\mathrm{CNCl}$
Answer:
(b) $\mathrm{CH}_3 \mathrm{CHO}$
Question 16.
Which one of the following reacts with $\mathrm{CH}_3 \mathrm{Mg}$ I followed by hydrolysis to yield tert. butyl alchol ?
(a) $\mathrm{CH}_3 \mathrm{CHO}$
(b) $\mathrm{HCHO}$
(c) $\mathrm{CH}_3 \mathrm{COOC}_2 \mathrm{H}_5$
(d) $\mathrm{CH}_3 \mathrm{COCH}_3$
Answer:
(d) $\mathrm{CH}_3 \mathrm{COCH}_3$
Question 17.
Which one of the following reacts with $\mathrm{CH}_3 \mathrm{Mg}$ I followed by acid hydrolysis to yield acetic acid ?
(a) $\mathrm{CNCl}$
(b) $\mathrm{CH}_3 \mathrm{COOC}_2 \mathrm{H}_5$
(c) $\mathrm{HCOOC}_2 \mathrm{H}_5$
(d) $\mathrm{CO}_2$
Answer:
(d) $\mathrm{CO}_2$
Question 18.
Which one of the following reagent react with methyl magnesium iodide followed by acid hydrolysis to give ethyl acetate?
(a) Chiorodimethyl ether
(b) Ethyl chloroformate
(c) Ethyl formate

(d) Acetaldehyde
Answer:
(b) Ethyl chioroformate
Question 19.
Which one of the following is used as fibre-swelling agent in textile processing?
(a) Chiorohenzene
(b) Chloroform
(c) Chlorai
(d) Chloroethane
Answer:
(a) Chiorobenzene
Question 20.
Which one of the fillowing is a gemdihalide?
(a) $\mathrm{CH}_3 \mathrm{CHCl}_2$
(b)

(c) $\mathrm{CH}_3-\mathrm{CH}_2 \mathrm{Cl}$
(d) $\mathrm{C}_6 \mathrm{H}_4 \mathrm{Cl}_2$
Answer:
(a) $\mathrm{CH}_3 \mathrm{CHCl}_2$
Question 21.
Which of the following reagent is used to distinguish gem-dihalides and vicinal dihalides?
(a) Alcoholic $\mathrm{KOH}$
(b) Aqueous $\mathrm{KOH}$
(c) $\mathrm{FeCl}_3 / \mathrm{Cl}_2$
(d) Ethanol
Answer:
(b) Aqueous $\mathrm{KOH}$
Question 22.
Which one of the following is used in the conversion of ethyliden dichioride to Acetylene?
(a) $\mathrm{Zn}+$ Methanol
(b) $\mathrm{KOH}+$ Ethanol
(c) Aqueous $\mathrm{NaOH}$
(d) Alcoholic $\mathrm{KOH}$
Answer:
(b) $\mathrm{KOH}+$ Ethanol
Question 23.
Which one of the following is used as a metal cleaning solvent?
(a) Isopropylidene chloride
(b) Methylene chloride
(c) Chloroform

(d) lodoform
Answer:
(b) Methylene chloride
Question 24 .
Which one of the following is used as an insecticide and as a soil sterilising agent?
(a) Chloroform
(b) Chlorai
(c) Chioropicrin
(d) Tetrachioromethane
Answer;
(c) Chloropicrin
Question 25.
Which one of the following is used to test primary amincs?
(a) Schiff's test
(b) Carbylarnine test
(c) Dye test
(d) Silver mirror test
Answer:
(b) Carbyianiine test
Question 26.
Which one of the following is used as propellant for aerosols and foams?
(a) Freons
(b) Methylidene chloride
(c) Chlorai
(d) Chloroform
Answer:
(a) Freons
Question 27.

the product X is ..................

Answer:

Question 28 .
Which one of the following will undergo $\mathrm{S}_{\mathrm{N}^1}$ reaction faster?

Answer:

Question 29.
Which one of the following compounds does not undergo nucleophilic substitution reactions at all?
(a) Ethyl bromide
(b) Vinyl chloride
(c) Benzyl chloride
(d) isopropyl chloride
Answer:
(b) Vinyl chloride
II. Match the following.
Question 1.

Answer:
$\begin{array}{lllll}(a) & 2 & 3 & 4 & 1\end{array}$
Question 2.

Answer:
$\begin{array}{lllll}(c) & 3 & 4 & 1 & 2\end{array}$
Question 3.

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

Answer:
$\begin{array}{lllll}\text { (b) } & 3 & 4 & 1 & 2\end{array}$
Question 5.

Answer:
(c) 4 3 1 2
Question 6.

Answer:
$\begin{array}{lllll}(c) & 4 & 3 & 1 & 2\end{array}$
III. Fill in the blanks.
Question 1.
........................ is used in the treatment of typhoid
Answer:
chloramphenicol
Question 2.
.................... is used in the treatment of malaria
Answer:
Chioroquine
Question 3.
........................... is used as an anesthetic .................
Answer:
Halothane
Question 4.
................................... is used for cleaning electronic equipments
Answer:
Trichioroethylene
Question 5.
The IUPAC name of $\mathrm{CH}_2=\mathrm{CH}-\mathrm{CH}_2 \mathrm{Cl}$ is ..........................
Answer:
3-Chioro-prop-1-ene
Question 6.
The structure of Vinyl iodide is ...............
Answer:
$\mathrm{CH}_2=\mathrm{CHI}$

Question 7.
2-iodo-2-methylpropane belongs to type .......................
Answer:
$3^{\circ}$ haloalkanes
Question 8.
The structure of 2-Iodo-2-methylpropanc is .................
Answer:

Question  9 .

the IUPAC name of this compound is .....................
Answer:
1-Bromo-2, 2-dimethyipropane
Question 10.
The IUPAC name of $\mathrm{CH}_2=\mathrm{CHCl}$ is ............
Answer:
Chioroethene
Question 11.

The IUPAC name of 

is
Answer:
2-Bromo-3-chloro-2, 4-dimethylpentane.
Question 12.

The IUPAC name of

 is ......................

Answer:
3-Chloro-2-methyl-prop- 1 -ene
Question 13.
The reactivity of haloacids $(\mathrm{HCl}, \mathrm{HBr}, \mathrm{HI})$ with alcohol is in the order ....................
Answer:
$\mathrm{HI}>\mathrm{HBr}>\mathrm{HCl}$
Question 14.
The decreasing order of bond length among alkyl halides $\left(\mathrm{CH}_2 \mathrm{I}, \mathrm{CH}_2 \mathrm{Br}, \mathrm{CH}_3 \mathrm{~F}, \mathrm{CH}_3 \mathrm{Cl}\right)$ is in the order ......................
Answer:
$\mathrm{CH}_3 \mathrm{~F}<\mathrm{CH}_3 \mathrm{Cl}<\mathrm{CH}_3 \mathrm{Br}<\mathrm{CH}_3 \mathrm{I}$
Question 15.
The bond strength of $\mathrm{C}-\mathrm{X}$ for the $\mathrm{C}-\mathrm{Cl}, \mathrm{C}-\mathrm{Br}, \mathrm{C}-\mathrm{I}, \mathrm{C}-\mathrm{F}$ decreases in the order is .....................
Answer:
$\mathrm{C}-\mathrm{F}<\mathrm{C}-\mathrm{Cl}<\mathrm{C}-\mathrm{Br}<\mathrm{C}-\mathrm{I}$
Question 16.
The catalyst used in Darzen halogenation of alcohol is ............
Answer:
Pyridine
Question 17.
In Finkeistein reaction, the mechanism followed is ..................
Answer:
$\mathrm{S}_{\mathrm{N}^2}$
Question 18 .
Silver salt of fatty acid is converted to bromo alkanc by ............
Answer:
Hunsdicker reaction

Question 19.
In Swarts reaction, chioroalkane is converted to .....................
Answer:
Fluoroalkane.
Question 20.
The conversion of bromoalkane to fluroalkane by heating with $\mathrm{AgF}$ is called .......................
Answer:
Swartz reaction
Question 21.
The decreasing order of boiling point of haloalkanes $\mathrm{CH}_3 \mathrm{Br}, \mathrm{CH}_3 \mathrm{Cl}, \mathrm{CH}_3 \mathrm{~F} \mathrm{CH}_3 \mathrm{I}$ is .......................
Answer:
$\mathrm{CH}_3 \mathrm{I}>\mathrm{CH}_3 \mathrm{Br}>\mathrm{CH}_3 \mathrm{CI}>\mathrm{CH}_3 \mathrm{~F}$
Question 22.
The correct increasing order of boiling point of haloalkanes $\mathrm{CH}_3 \mathrm{Cl}, \mathrm{CHCl}_3, \mathrm{CH}_2 \mathrm{Cl}_2, \mathrm{CCl}_4$ is .......................
Answer:
$
\mathrm{CCl}_4>\mathrm{CHCl}_3>\mathrm{CH}_2 \mathrm{Cl}_2>\mathrm{CH}_3 \mathrm{Cl}
$
Question 23.
Haloalkanes reacts with aqueous solution of $\mathrm{KOH}$ to form ...............
Answer:
Alcohol
Question 24 .
Haloalkane reacts with alcoholic solution of $\mathrm{KOH}$ to form ..................
Answer:
Alkene
Question 25.
Ethyl bromide reacts with alcoholic $\mathrm{AgCN}$ to form ............
Answer:
$\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{NC}$

Question 26 .
Ethyl bromide reacts with alcoholic $\mathrm{KNO}_2$ to form .................
Answer:
Ethyl nitrite
Question 27.
The reaction in which sodium alkoxide react with haloalkane to form ether in called ..................
Answer:
Williamson's synthesis
Question 28.
Primary alkyl halide react with aqueous $\mathrm{NaOH}$ follows ...................
Answer:
$\mathrm{S}_{\mathrm{N}^2}$
Question 29.
Tertiary butyl bromide reacts with aqueous $\mathrm{KOH}$ follows ....................
Answer:
$\mathrm{S}_{\mathrm{N}^2 \text { mechanism }}$
Question 30.
Ethyl bromide reacts with alcoholic $\mathrm{KOH}$ following mechanism. .............................
Answer:
$\mathrm{E}_1$
Question 31.
The product formed when tertiary butyl chloride is treated with alcoholic $\mathrm{KOH}$ is ....................
Answer:
Iso-butylene
Question 32.
When 2-bromobutane react with alcoholic $\mathrm{KOH}$, the products formed are ....................
Answer;
1-butene & 2-butene
Question 33.
The product formed when iodoethane is treated with $\mathrm{HI}$ in the presence of red phosphorous is ......................
Answer:
$\mathrm{CH}_3-\mathrm{CH}_3$

Question 34.

............... is used as antiseptic
Answer:
Iodoform
Question 35.

......................is used for extinguishing the fire caused by oil or petrol under the commercial name pyrene

Answer:
Tetrachioromethane
Question 36.
.......................... Ethyl formate reacts with methyl magnesium iodide followed by acid hydrolysis to yield

Answer:
Acetaldehyde
Question 37.
..................... Ethyl-methyl ether ethene is obtained by the action of methyl magnesium iodide with

Answer:
Chioro-aimethyl-ether
Question 38.
The hybridised state of carbon in haloarenes is .............
Answer:
$\mathrm{sp}^2$
Question 39.
The catalyst used in the preparation of chiorobenzene from benzene is. ......................
Answer:
$\mathrm{FeCl}_3$
Question 40 .
In the Gattermann reaction of preparation of chiorobenzene from benzene, the catalyst used is .....................
Answer:
$\mathrm{Cu} / \mathrm{HCl}$
Question 41.
The conversion of benzene diazoniurn chloride to chiorobenzene in the presence of $\mathrm{Cu}_2 \mathrm{Cl}_2+\mathrm{HCl}$ is named as ........................
Answer:
Sandmeyer reaction
Question 42 .
Fluorobenzene is prepared from benzene diazonium chloride by .............
Answer:
BaIz-Scheimann reaction

Question 43.
Conversion of benzene to chiorobenzene in the presence of $\mathrm{CuCl}_2 / \mathrm{HCl}$ is named as ................

Answer:
Gattermann reaction
Question 44 .
The conversion of chiorobenzene to phenol by the action of $\mathrm{NaOH}$ is called ....................
Answer: 
Dow's process
Question 45 .
In Wurtz fittig reaction, chiorohenzene is converted to .................................... by reacting it with ethyl chloride.
Answer:
Ethylbenzene
Question 46.
The product obtained in fittig reaction of chiorobenzene is .................
Answer:
Biphenyl
Question 47.
The reagent used in the conversion of Chiorobenzene to Benzene is ....................
Answer:
$\mathrm{Ni}-\mathrm{Al} / \mathrm{NaOH}$
Question 48.
The catalyst used in the preparation of Phenyl magnesium chloride from chiorobenzene is .....................
Answer:
THF
Question 49.
Iso-propylidene chloride is an example of .....................
Answer:
vicinal dihalide
Question 50 .

The IUPAC name of   is ...............
Answer:
1,2-dibromo-2-methylpropane
Question 51.
The reagent used in the conversion of ethylene dichioride is ....................
Answer:
$
\mathrm{Zn}+\mathrm{CH}_3 \mathrm{OH}
$
Question 52.
Chloroform is converted to methylene-chioride by the action of ...................
Answer:
$\mathrm{Zn}+\mathrm{HCl}$ and $\mathrm{H}_2 / \mathrm{Ni}$
Question 53.
The reagents used in the preparation of chloroform are ..................
Answer:
Ethanol + Bleaching powder
Question 54.
The formula of Chioropicrin is ..................
Answer: 
$
\mathrm{CCl}_3 \mathrm{NO}_2
$

Question 55.
The product formed when methylamine react with chloroform and alkali is .,.......................
Answer:
$\mathrm{CH}_3 \mathrm{NC}$
Question 56.
The product formed when CCI4 reacts with hot water vapours is ...................
Answer:
$\mathrm{COCl}_2$
Question 57.
The formula of Freon -11 is ..................
Answer: 
$\mathrm{CFCl}_3$
Question 58 . 
The formula of Freon -12 is ................
Answer:
$\mathrm{CF}_2 \mathrm{Cl}_2$
Question 59.
The catalyst used in the preparation of $\mathrm{CCl}_2 \mathrm{~F}_2$ from $\mathrm{CCl}_4$ and $\mathrm{HF}$ is ....................
Answer:
$\mathrm{SbCl}_5$
Question 60 .
The reagents used to prepare DDT are ............................
Answer:
Chlorai and Chiorobenzene
Question 61.
........................ is used to kill various insects like housefly and mosquitoes.
Answer:
(c) DDT
Question 62.
The name of $\mathrm{CFCl}_3$ is ....................
Answer:
Freon-11
Question 63.
The treatment of acetone with excess of $\mathrm{RMgX}$ gives:.. ...................

Question 64.
The most easily hydrolysed molecule under $\mathrm{S}_{\mathrm{N}^2}$ reaction is ..................
Answer:
Ten. butyl chloride
Ouestion 65 .

The product ' $\mathrm{X}$ ' is .............

Answer:
Ethanol
Question 66.
 The product ' $\mathrm{X}$ ' is .............
Answer:
$
\mathrm{CH}_4
$
Question 67.
On heatrng $\mathrm{CHCl}_3$ with aqueous $\mathrm{NaOH}$ solution, the product formed is ..............

Answer: 
$
\mathrm{HCOONa}
$
Question 68.
Depletion of ozone layer is caused by ..........
Answer:
Freons
Question 69.
Chloropicrin is used as ..............
Answer:
soil sterilizing agent
Question 70 .
lodoform can be used as ...................
Answer:
Antiseptic.
Question 71.
in oil fire extinguisher, the compound used pyrene is chemically ..........
Answer:
$
\mathrm{CCl}_4
$
Question 72 .
Reaction of ethyl chloride with sodium metal leads to the formation of .......................

Answer:
n-Butane
Question 73.
When chloroform is treated with primary amine and $\mathrm{KOH}$, we get
Answer:
Offensive odours
IV. Choose the odd one out.
Question 1.
(a) $\mathrm{CH}_3 \mathrm{Br}$
(b) $\mathrm{CH}_3-\mathrm{CH}_2 \mathrm{Br}$
(c) $\left(\mathrm{CH}_3\right)_3 \mathrm{C}-\mathrm{Br}$
(d) $\mathrm{CH}_3-\mathrm{CH}_2-\mathrm{CH}_2 \mathrm{Br}$
Answer:
(c) $\left(\mathrm{CH}_3\right)_3 \mathrm{C}-\mathrm{Br}$. It is a haloalkane whereas others are $1^{\circ}$ haloalkanes.
Question 2.
(a) Finkeistein reaction
(b) Wurtz reaction
(c) Swarts reaction
(d) Friedel crafts alkylation
Answer:
(d) Friedel crafts alkylation. It is used to prepare aromatic hydrocarbon whereas others are used to prepare alkanes.
Question 3.
(a) $\mathrm{PCl}_5$
(b) $\mathrm{SOCl}_2$
(c) $\mathrm{HCl}$
(d) $\mathrm{HF}$
Answer:
(cl) HF It is not used to prepare directly fluoro alkane whereas others are used to prepare directly chioro alkanes.
Question 4.
(a) Aerosol spray propellant
(b) Metal cleaning agent
(c) Anaesthetic agent
(d) Solvent in paint remover
Answer:
(c) Anaesthetic agent. It is not the use of methylene chloride whereas others are uses of methylene chloride.
V. Choose the correct pair.

Question 1.
(a) Chiorobenzene + chloral : DDT
(b) Chloroform $+\mathrm{HNO}_3:$ Phosgene
(c) Chloroform $+\mathrm{Zn} / \mathrm{HCl}$ : Methyl isocyanide
(d) Methane $+4 \mathrm{Cl}_2$ : Carbon tetra chloride
Answer:
(c) Chlorobenzene + chloral : DDT
Question 2.
(a) Chloroform : Analgesic
(b) Freon : Propellant
(c) Chioropicrin: Antiseptic
(d) DDT : Soil sterilizing agent
Answer:
(b) Freon : Propellant
Question 3.
(a) Freon : Refrigerant
(b) DDT : Antiseptic
(c) Methylene : Soil sterilizing agent
(d) Iodotorni : Anaesthetic
Answer:
(a) Freon : Refrigerant
Question 4.
(a) $\mathrm{HCOH}+\mathrm{CH}_3 \mathrm{MgI}$ : Secondary alcohol
(b) $\mathrm{CH}_3 \mathrm{CHO}+\mathrm{CH}_3 \mathrm{MgI}:$ Tertiary alcohol
(c) $\mathrm{CH}_3 \mathrm{COCH}_3+\mathrm{CH}_3 \mathrm{MgI}$ : Primary alcohol
(d) $\mathrm{CO}_2+\mathrm{CH}_3 \mathrm{MgI}:$ Acetic acid
Answer:
(d) $\mathrm{CO}_2+\mathrm{CH}_3 \mathrm{MgI}$ : Acetic acid

Question 5.
(a) $\left(\mathrm{C}_3 \mathrm{H}\right)_3 \mathrm{C}-\mathrm{Cl}+$ alcoholic $\mathrm{KOH}: \mathrm{S}_{\mathrm{N}^1}$ reaction
(b) $\left(\mathrm{CH}_3\right)_3 \mathrm{C}-\mathrm{Cl}+$ alcoholic $\mathrm{KOH}: \mathrm{E}_1$ reaction
(c) $\left(\mathrm{CH}_3\right)_3 \mathrm{C}-\mathrm{Cl}+$ aqueous $\mathrm{KOH}: \mathrm{S}_{\mathrm{N}^2}$ reaction
(cl) $\mathrm{CH}_3-\mathrm{Cl}+$ aqueous $\mathrm{KOH}: \mathrm{S}_{\mathrm{N}^1}$ reaction
Answer:
(b) $\left(\mathrm{CH}_3\right)_3 \mathrm{C}-\mathrm{Cl}+$ alcoholic $\mathrm{KOH}: \mathrm{E}_1$ reaction
VI. Choose the incorrect pair.
Question 1.

Answer:

Question 2.
(a) $\mathrm{CH}_3 \mathrm{I}>\mathrm{CH}_3 \mathrm{Br}>\mathrm{CH}_3 \mathrm{Cl}>\mathrm{CH}_3 \mathrm{~F}$ : decreasing order of boiling point
(b) $\mathrm{CCl}_4>\mathrm{CHCl}_3>\mathrm{CH}_2 \mathrm{Cl}_2>\mathrm{CH}_3 \mathrm{Cl}$ : increasing order of boiling point
(c) $\mathrm{CH}_3-\mathrm{CH}_2-\mathrm{CH}_2 \mathrm{Cl}<\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{Cl}<\mathrm{CH}_3 \mathrm{Cl}$ : increasing order of boiling point

Answer:
(c) $\mathrm{CH}_3-\mathrm{CH}_2-\mathrm{CH}_2 \mathrm{Cl}<\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{Cl}<\mathrm{CH}_3 \mathrm{Cl}$ : increasing order of boiling point
Question 3.
(a) $\left(\mathrm{CH}_3\right)_3 \mathrm{C}-\mathrm{Br}+$ aqueous $\mathrm{KOH}: \mathrm{S}_{\mathrm{N}^1}$ reaction
(b) $\left(\mathrm{CH}_3\right)_3 \mathrm{C}-\mathrm{Br}+$ alcoholic $\mathrm{KOH}: \mathrm{E}_1$ reaction
(c) $\mathrm{CH}_3 \mathrm{Br}$ - aqueous $\mathrm{KOH}: \mathrm{E}_2$ reaction
(d) $\mathrm{CH}_3 \mathrm{Br}+$ aqueous $\mathrm{KOH}: \mathrm{S}_{\mathrm{N}^2}$ reaction
Answer:
(c) $\mathrm{CH} 3 \mathrm{Br}+$ aqueous $\mathrm{KOH}: \mathrm{E}_2$ reaction
Question 4.
(a) 1-chioro propane + Alcoholic $\mathrm{KOH}$ : Propene
(b) Tert.butyl bromide + Alcoholic $\mathrm{KOH}$ : Isobutylenc
(c) $\mathrm{CH}_3-\mathrm{CH}_2 \mathrm{I}+\mathrm{HI}+$ Red p : Ethanc
(d) $\mathrm{CH}_3 \mathrm{CHO}+\mathrm{CH}_3 \mathrm{Mg}$ I : Ten. Butyl alcohol
Answer:
(d) $\mathrm{CH}_3 \mathrm{CHO}+\mathrm{CH}_3 \mathrm{Mg}$ I : Ten. Butyl alcohol
Question 5 .
(a) $\mathrm{HCHO}+\mathrm{CH}_3 \mathrm{MgI}$ : Primary alcohol
(b) $\mathrm{CH}_3 \mathrm{CHO}+\mathrm{CH}_3 \mathrm{MgI}:$ Secondary alcohol
(c) $\mathrm{CH}_3 \mathrm{COCH}_3+\mathrm{CH}_3 \mathrm{MgI}$ : Aromatic alcohol
(d) $\mathrm{CO}_2+\mathrm{CH}_3 \mathrm{MgI}:$ Acetic acid
Answer:
(c) $\mathrm{CH}_3 \mathrm{COCH}_3+\mathrm{CH}_3 \mathrm{MgI}$ : Aromatic alcohol
VII. Assertion & Reason.
Question 1 .
Assertion (A): The C-I in $\mathrm{CH}_3 \mathrm{X}$ is weak.
Reason (R): Larger the size, greater is the bond length and weaker is the bond formed.
(a) Both (A) and (R) are correct and (R) is the correct explanation of (A).
(b) Both (A) and (R) are correct but (R) is the correct explanation of (A).
(c) $(A)$ is correct but $(\mathrm{R})$ is wrong.
(d) (A) is wrong but $(R)$ is correct.

Answer:
(a) Both (A) and (R) are correct and (R) is the correct explanation of (A).
Question 2.
Assertion (A): Haloalkanes have higher boiling point and melting point than the parent alkanes having the same number of carbon.
Reason (R): The intermolecular forces of attraction and dipole-dipole interactions are stronger in haloalkanes.
(a) Both (A) and (R) are correct and (R) is the correct explanation of (A).
(b) Both (A) and (R) are correct but (R) is not the correct explanation of (A).
(c) (A) is correct but $(R)$ is wrong.
(d) (A) is wrong but (R) is correct.
Answer:
(a) Both (A) and (R) are correct and (R) is the correct explanation of (A).
Question 3.
Assertion (A) : Among isomenc halides, the boiling point decreases with increase in branching in alkyl group.
Reason (R) : With the increase in branching, the molecule attains spherical shape with less surface area and less forces of interaction.
(a) Both (A) and (R) are correct and (R) is not the correct explanation of (A).
(b) Both (A) and (R) are correct and (R) is the correct explanation of (A).
(c) (A) is correct but $(R)$ is wrong.
(d) (A) is wrong but $(\mathrm{R})$ is correct.
Answer:
(a) Both (A) and (R) are correct and (R) is the correct explanation of (A).
Question 4.
Assertion (A): The melting point of para halóbenzene is higher than that of ortho and meta isomers. Reason (R): The higher melting point of $\mathrm{p}$-isomer is due to its symmetry which leads to more close packing of its molecules in the crystal and subsequently p-isomer have strong intermolecular attractive forces.
(a) both (A) and (R) are correct and (R) is the correct explanation of(A).
(b) Both (A) and (R) are correct but (R) is not the correct explanation of $(A)$.
(c) (A) is correct but $(\mathrm{R})$ is wrong.
(d) (A) is wrong but (R) is correct.
Answer:
(a) both (A) and (R) are correct and (R) is the correct explanation of(A).
Question 5.
Assertion (A) : Haloarenes are insoluble in water.
Reason (R) : Haloarenes are able to form hydrogen bonds with water.
(a) Both (A) and (R) are correct but (R) is the correct explanation of (A).
(b) both (A) and (R) are correct and (R) is not the correct explanation of (A).
(e) (A) is correct but $(R)$ is wrong.
(d) (A) is wrong but $(\mathrm{R})$ is correct
Answer:
(c) (A) is correct but (R) is wrong.

Question 6.
Assertion (A) : Haloarenes do not undergo nucleophilic substitution reactions readily.
Reason (R) : The $\mathrm{C}-\mathrm{X}$ bond in aryl halides is short and stronger and also the aromatic ring is a center of
high electron density.
(a) Both (A) and (R) are correct and (R) is the correct explanation of (A).
(h) Both (A) and (R) are correct but (R) is not the correct explanation of (A).
(c) (A) is correct but $(\mathrm{R})$ is wrong.
(d) (A) is wrong but (R) is correct.
Answer:
(a) Both (A) and (R) are correct and (R) is the correct explanation of (A).
Question 7.
Assertion (A): Chloroform vapours can be used as an anaesthetic.
Reason (R): Chloroform vapours depresses the central nervous system and cause unconsciousness.
(a) Both (A) and (R) are correct but (R) is not the correct explanation of (A).
(b) Both (A) and (R) are correct and (R) is the correct explanation of (A).
(c) (A) is correct but $(R)$ is wrong.
(d) (A) is wrong but $(\mathrm{R})$ is correct.
Answer:
(a) Both (A) and (R) are correct and (R) is the correct explanation of (A).
Question 8.
Assertion (A): Nowadays chloroform is not used as an anaesthetic.
Reason (R): Chloroform undergoes oxidation in the presence of light and air to form highly poisonous phosgene.
(a) Both (A) and (R) are correct and (R) is the correct explanation of (A).
(b) Both (A) and (R) are correct but (R) is not the correct explanation of (A).
(c) (A) is correct but $(\mathrm{R})$ is wrong.
(cl) (A) is wrong but (R) is correct.
Answer:
(a) Both (A) and (R) are correct and (R) is the correct explanation of (A).
Question 9.
Assertion (A): DDT is banned now-a-days.
Reason (R): DDT has a long term toxic effect.
(a) Both assertion and reason are true and reason is the correct explanation of assertion.

(b) Both assertion and reason are true but reason is not the correct explanation of assertion.
(c) Assertion is true but reason is false.
(d) Assertion is false but reason is true.
Answer:
(a) Both assertion and reason are true and reason is the correct explanation of assertion.

VIII. Choose the correct statement.
Question 1.
(a) Halo alkanes have higher boiling point than the parent alkane with same number of carbons because of strong inter molecular forces of attraction.
(b) The boiling point of halo alkanes decreases with the increase of halogen atoms.
(c) The boiling point of mono halo alkanes decreases with the increase in the number of carbon atoms.
(d) Halo alkanes are soluble in water.
Answer:
(a) Halo alkanes have higher boiling point than the parent alkane with same number of carbons because of strong inter molecular forces of attraction.
Question 2.
(a) Halo alkanes are soluble in water.
(b) The boiling point of halo alkanes increase with the increase in the number of halogen atoms.
(c) The melting point of mono halo alkane decrease with the increase in the number of carbon atoms.
(d) The density of alkyl halides are lesser than those of hydrocarbons of comparable molecular weight.
Answer:
(b) The boiling point of halo alkanes increase with the increase in the number of halogen atoms.
Question 3.
(a) Williamson's synthesis of ether is an example of nucleophilic substitution reaction.
(b) Reaction of methyl bromide with aqueous potassium hydroxide is an example ofelimination reaction.
(c) Reaction of Tertiary butyl bromide with alcoholic $\mathrm{KOH}$ is an example of SN2 reaction.
(d) Reaction of Tertiary butyl bromide with alcoholic $\mathrm{KOH}$ is an example of $\mathrm{E}$, reaction.
Answer:
(a) Williamson's synthesis of ether is an example of nucleophilic substitution reaction.
2 Marks Questions and Answers

Question 1.
Write the IUPAC names of -
1. $\mathrm{CH}_2=\mathrm{CHCI}$
2. $\mathrm{CH}_2=\mathrm{CH}-\mathrm{CH}_2 \mathrm{Br}$.
Answer:
1. $\mathrm{CH}_2=\mathrm{CHCl}:$ Chloroethene
2. $\mathrm{CH}_2=\mathrm{CH}-\mathrm{CH}_2 \mathrm{Br}: 3$-Bromo-prop- 1-ene
Question 2.
Write the structural formula of the following compounds:
1. 2-Chloro-2-Methylpropane
2. 1 -Bromo-2, 2-Dimethylpropane
Answer:
1. 2-Chloro-2-Methylpropane

$\text { 2. } 1 \text {-Brorno-2, 2-dimethyipropane }$

Question 3.
How many isomers are possible for the formula $\mathrm{C}_3 \mathrm{H}_7 \mathrm{~F}$ ? Give their structures and names.
Answer:
$\mathrm{C}_3 \mathrm{H}_7 \mathrm{~F}-2$ isomers are possible.
1. $\mathrm{CH}_3-\mathrm{CH}_2-\mathrm{CH}_2 \mathrm{~F}-1$ - fiuoropropene

2. 

Question 4.
Write the isomeric structures and names for the formula $\mathrm{C}_2 \mathrm{H}_4 \mathrm{Cl}_2$.
Answer:

Ethylene dichioride (or) 1,2-dichioroethane.

Ethylidene chloride (or) 2-dichioroethane.
Question 5.
Draw the structures of -
1. 1-brorno-2,3-dichiorobutane
2. 2-bromo-3-chloro-2, 4-dimethyl pentane
Answer:
1. 1 -bromo-2, 3-dichiorobutane

$\text { 2. 2-bromo-3-chloro-2, 4-dimethy } 1 \text { pentane }$

Question 6.
What happens when $\mathrm{HI}$ reacts with ten. butyl alcohol?
Answer:

Question 7.
Explain the action of
(i) $\mathrm{PCl}_5$
(ii) $\mathrm{PCl}_3$ with ethanol.
Answer:

(i)

(ii)

Question 8.
How does $\mathrm{HBr}$ react with propene?
Answer:
Propene react with $\mathrm{HBr}$ and follows Markovnikov's rule.

Question 9.
How methane reacts with $\mathrm{Cl}_2$ in the presence of light?
Answer:

Question 10.
Explain-Finkelstein reaction.
Answer:
Chioro (or) bromoalkane on heating with sodium iodide in dry acetone gives jodo alkane. This reaction is called Finkeistein reaction.

Question 11.
Explain Swans reaction.
Answer:
Chioro (or) bromoalkanes on heating with $\mathrm{AgF}$ give fluoroalkanes. This reaction is called Swans reaction.

Question 12 .
What happens when silver propionate reacts with $\mathrm{Br}$, in $\mathrm{CCl}_4$ ?
Answer:
Silver salt of fatty acids $\left(\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{COOAg}\right)$, e.g., silver propionate treated with $\mathrm{Br}_2 / \mathrm{CCl}_4$ gives bromoalkane. This reaction is called Hunsdicker reaction.

Question 13.
Haloalkanes have higher boiling point and melting point than the parent alkane. Justify this statement.
Answer:
Haloalkanes have higher boiling point than the parent alkane having the same number of carbon atoms because the intermolecular forces of attraction and dipole-dipole interactions are comparatively stronger in haloalkanes.
Question 14.
$\mathrm{CCl}_4>\mathrm{CHCl}_3>\mathrm{CH}_2 \mathrm{Cl}_2>\mathrm{CH}_3 \mathrm{Cl}$ is the decreasing order of boiling point in haloalkanes. Give reason.
Answer:
The boiling point of chioro, bromo and iodoalkanes increases with increase in the number of halogen atoms. So the correct decreasing order of boiling point of haloalkanes is:
$
\mathrm{CCl}_4>\mathrm{CHCl}_3>\mathrm{CH}_2 \mathrm{Cl}_2>\mathrm{CH}_3 \mathrm{Cl} \text {. }
$
Question 15.
Arrange the following in increasing order of boiling point. Give reason.
$
\left(\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{CH}_2 \mathrm{Cl}, \mathrm{CH}_3 \mathrm{CH}_2 \mathrm{Cl}, \mathrm{CH}_3 \mathrm{Cl}\right)
$
Answer:
The correct order of boiling point of haloalkanes is:
$
\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{CH}_2 \mathrm{Cl}>\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{Cl}>\mathrm{CH}_3 \mathrm{Cl} \text {. }
$
The boiling point of monoalkanes increase with the increase in the number of carbon atoms.
Question 16.
Why haloalkanes arc insoluble in water but soluble in organic solvents?
Answer:
Haloalkanes are polar covalent compounds, soluble in organic solvents, but insoluble in water because they are unable to form hydrogen bond with water molecules.
Question 17.
What happens when bromoethane is treated with moist silver oxide?
Answer:
When bromoethane is treated with moist silver oxide, ethanol will be formed as product:

Question 18 .
Complete the following reactions:

(i)

(ii)

Answer:

(i)

(ii)

Question 19
Explain the action of sodium hydrogen suiphide with bromoethane?
Answer:

Question 20 .
Explain Williamson's synthesis.
Answer:
Williamson's synthesis:
Haloalkanes when boiled with sodium alkoxide gives the corresponding ether.

Question 21.
Explain the action of alcoholic potash with bromoethane.
Answer:
Elimination reaction takes place when alcoholic potash reacts with bromoethane:

Question 22.
State-Saytzeff's rule.
Answer:
Some haloalkanes when treated with alcoholic $\mathrm{KOH}$ yield a mixture of olefins with different amounts. It is explained by Saytzeff's rule which states that in a dehydrohalogenation reaction, the preferreed product is that alkene which has more number ofalkyl group attached to the doubly bonded carbon atom.
Question 23.
How will you convert 1-chioropropanc to propene?
Answer:

Question 24.
What is Grignard reagent? How is it prepared from ethyl bromide?
Answer:
When a solution of haloalkane in either is treated with magnesium, we will get alkyl magnesium halide
known as Grignard reagent, ethyl magnesium bromide is prepared from ethyl bromide as:

Question 25.
How will you prepare ethyl lithium'?
Answer:
When bromoethane is treated with an active metal like lithium in the presence of dry ether, then ethyl lithium will be formed.

Question 26.
What is tetraethyl Lead? How is it prepared?

Answer:

Question 27.
Convert bromoethane to ethane.
Answer:

Question 28.
How is iodoethane converted to ethane?
Answer:

Question 29.
Starting from $\mathrm{CH}_3 \mathrm{MgI}$, how will you prepare acetaldehyde?
Answer:

Question 30.
How will you get acetone from methyl manesium iodide?
Answer:

Question 31.
Explain the action of Ethyl chioroformate with Methyl magnesium iodide.
Answer:
Ethyl chioroformate reacts with Grignard reagent to form esters as follows:

Question 32.
Write the IUPAC names of: $\mathrm{F}$

(i)

(ii)

Answer:

(i)

1- bromo-4-fluoro-2-iodobenzene 

(ii)

1- bromo-2-fluoro-4-iodobenzene 

Question 33.
How is benzene directly converted to chiorobenzene?
Answer:

Question 34.
Explain Sandmeyer's reaction.
Answer:
Sandmeyer's reaction:
The reaction in which benzene-diazonium chloride is converted to chiorobenzene on heating it with $\mathrm{Cu}_2 \mathrm{Cl}_2 / \mathrm{HCl}$ is known as sand Meyer's reaction.

Question 35 .
Explain Gattcrrnann reaction.
Answer:
Gattermann reaction:
The reaction in which benzene diazonium chloride react with copper in the presence of $\mathrm{HCl}$, chlorobenzene is formed, called Gatterrnann reaction.

Question 36.
How will you prepare iodobenzene?
Answer:

Question 37.
Explain-Balz-Schiernann reaction.
Answer:
Fluorobenzene is prepared by treating benzene diazonium chloride with fluoro boric acid. This reaction produces diazonium fluoroborate which on heating produce fluorobenzene. this reaction is called BalzSchiernann reaction.

Question 38 .
p-dichlorobenzcnc has higher melting point than ortho and meta dichloro benzene. Why?
Answer:
The melting point of p-dichloro benzene is higher than the melting point of the corresponding ortho and mcta isomers. The higher melting which leads to more close packing of its molcules in the crystal lattice and consequently strong intermolecular attractive forces which requires more energy for melting.
p-dichlorobenzene $>$ o-dichlorobenzene $>$ m-dichlorobenzene
Question 39.
Explain Wurtz-fitting reaction.
Answer:
Wurtz-fitting reaction:
Chlorobenzene and chioroethane are heated with sodium in ether solution to form ethylbenzene. This reaction is called Wurtz-fitting reaction.

Question 40 .
How will you get benzene from chlorobenzene?
Answer:
Chiorobenzene is reduced with $\mathrm{Ni}-\mathrm{Al}$ Alloy in the presence of $\mathrm{NaOH}$ to give benzene.

Question 41.
Explain about the preparation of phenyl magnesium chloride.
Answer:

Question 42.
How will you prepare ethylidcne dichioride from acetylene?
Answer:

Question 43 .
What is gern-dihalide? Give one example and explain its preparation.
Answer:
1. If two halogen atoms are attached to one carbon atom of alkyl halide, it is named as gem dihalide. e.g., $\mathrm{CH}_3-\mathrm{CHCl}_2$ (ethylidene dichloride.)
2. Preparationof $\mathrm{CH}_3-\mathrm{CHCl}_2$ :

Question 44.
Explain the action of zinc and $\mathrm{HCl}$ on chloroform.
Answer:

Question 45 .
How does nickel react with chloroform?
Answer:

Question 46 .
Convert methane to methylene chloride.
Answer:

Question 47.
Explain Carbylamine reaction. (or) Give the characteristic test for primary amine.
Answer:
Chlorofonn reacts with aliphatic or aromatic primary amines and alcoholic caustic potash to give foul smelling alkyl isocyanide (carbylamine).

Question 48.
How will you prepare carbon tetrachioride?
Answer:
The reaction of methane with excess of chlorine in the presence of sunlight give carbon tetrachioride as major product.

Question 49.
How will you convert carbon tetrachioride to chloroform?
Answer:

Question 50.
What are freons? How are they named? Give two examples.
Answer:
(i) The chioro-fluoro derivatives of methane and ethane are called freons.
(ii) Freon is represented as freon-cba
$\mathrm{c}=$ number of $\mathrm{C}$ atoms -
$\mathrm{b}=$ number of $\mathrm{H}$ atoms +1
$a=$ total number ofF atoms

Question 51.
What are ambident nucleophiles'? Explain with an example.
Answer:
Nucleophiles which can attack through two different sites are called ambident nucicophiles. For example, cyanide group is a resonance hybrid of two contributing structures and therefore it can act as a nucleophile in two different ways:
$
{ }^{\circ} \mathrm{C} \equiv \mathrm{N} \longleftrightarrow: \mathrm{C}=\mathrm{N}^{\circ}
$
It can attack through carbon to form cyanides and through nitrogen to form isocyanides or carbylamines.
Question 52.
Which compound in each of the following pairs will react faster in $\mathrm{S}_{\mathrm{N}^2}$ reaction with $\mathrm{OH}$ ion?
1. $\mathrm{CH}_3 \mathrm{Br}$ or $\mathrm{CH}_3 \mathrm{I}$
2. $\left(\mathrm{CH}_3\right)_3 \mathrm{CCl}$ or $\mathrm{CH}_3 \mathrm{Cl}$
Answer:
1. Since $\mathrm{I}^{-}$ion a better leaving group than $\mathrm{Br}^{-}$ion, therefore $\mathrm{CH}_3 \mathrm{I}$ will react faster than $\mathrm{CH}_3 \mathrm{Br}^{\text {in }} \mathrm{S}_{\mathrm{N}^2}$ reaction with $\mathrm{OH}^{-}$ion.
2. On steric grounds $1^{\circ}$ alkyl halides are more reactive than tert alkyl halide in $\mathrm{S}_{\mathrm{N}^2}$ reactions. Therefore, $\mathrm{CH}_3 \mathrm{Cl}$ will react at a faster rate than $\left(\mathrm{CH}_3\right)_3 \mathrm{CCl}$ in a $\mathrm{S}_{\mathrm{N}^2}$ reaction with $\mathrm{OH}^{-}$ion.
Question 53.
The treatment ofalkyl chlorides with aqueous $\mathrm{KOH}$ solution leads to the formation of alcohols but in the presence of alcoholic $\mathrm{KOH}$ solution, alkenes are the major product. Explain.
Answer:
In aqueous solution, $\mathrm{KOH}$ is almost completely ioniscd to give $\mathrm{OH}^{-}$ions which being a strong nucleophile brings about a substitution reaction of alkyl halides to form alcohols. In aqueous solution, $\mathrm{OH}^{-}$ions are highly hydrated. This solvation reduces the basic character of $\mathrm{OH}^{-}$ions which therefore, abstract fails to abstract a hydrogen atom from the n-carbon of the alkyl chloride to form an alkene. In contrast, an alcoholic solution of $\mathrm{KOH}$ contains alkoxide $\left(\mathrm{RO}^{-}\right)$ions which being a much stronger base than $\mathrm{OH}^{-}$ions preferentially eliminates a molecule of $\mathrm{HCl}$ from an alkyl chloride to form alkenes.
Question 54.
Give one example of each of the following reactions:
1. Wurtz Reaction
2. Wurtz - Fittig reaction
Answer:
1. Wurtz Reaction:
It involves conversion of alkyl halides into alkane.
Example:

2. Wurtz-Fittig reaction:
It involves the reaction of an aryl halide and alkyl halide to form the corresponding hydrocarbon.

Question 55.
How will you distinguish between the following pair of compounds:
1. Chloroform and carbon tetrachioride,
2. Benzyl alcohol and chiorobenzene.
Answer:
1. On heating chloroform and carbon tetrachloride with aniline with ethanoic acid and potassium hydroxide separately, chloroform forms a pungent smelling isocyanide compound but carbon tetrachloride does not form this compound.
2. On adding sodium hydroxide and silver nitrate to both the compounds, benzyl chloride forms a white precipitate but chiorobenzene does not form any white precipitate.
3 Marks Questions And Answers
Question 1.
Give one example with structure and name for each of the following compounds.
(a) Primary haloalkane
(b) Secondary haloalkane
(c) Tertiary haloalkane
Answer:
(a) Primary haloalkane

(b) Secondary haloalkane

(c) Tertiary haloalkane 

Question 2.
Write the possible isomers for the formula $\mathrm{C}_4 \mathrm{H}_9 \mathrm{Cl}$ with structures and names.
Answer:
$\mathrm{C}_4 \mathrm{H}_9 \mathrm{Cl}$ (4 isomers):

Question 3:

Answer:
For a compound with molecular formula $\mathrm{C}_4 \mathrm{H}_9 \mathrm{Cl}-3$ isomers $\left(1^{\circ}, 2^{\circ}, 3^{\circ}\right)$ arc possible. Among the isomeric alkyl halides, the boiling point decreases with the increase in branching in the alkyl chain. This is because with increase in branching, the molecule attains spherical shape with less surface area. As a result, the intermolecular forces become weak, resulting in lower boiling point. Therefore the boiling point decreases in the order:

Hence, $\left(\mathrm{CH}_3\right)_3 \mathrm{C}-\mathrm{Cl}$ has the lowest boiling point.
Question 4.
Explain ammonolysis of haloalkanes. (or) How excess of haloalkanc react with alcoholic ammonia?
Answer:
With excess of haloalkanes, ammonia react to give primary, secondary, tertiary amines along with
quarternary ammonium salt:

Question 5.
Explain how bromoethane reacts with -
1. alcoholic $\mathrm{KCN}$
2. alcoholic $\mathrm{AgCN}$
Answer:
1. Bromoethanc reacts with alcoholic $\mathrm{KCN}$ to form ethyl cyanide.

2. Bromoethane reacts with alcoholic AgCN to form alkyl isocyanide.

Question 6.
Explain the hydrolysis of 2-bromobutane with aqueous $\mathrm{KOB}$.
Answer:
- 2-bromobutane is optically active and it undergoes $\mathrm{S}_{\mathrm{N}^1}$ reaction with aqueous $\mathrm{KOH}$.
- The product obtained will be an optically inactive racemic mixture.
- As nucleophilic reagent $\mathrm{OH}^{-}$ion can attack the carbocation from both sides to form equal proportions of dextro and levo rotatory optically active isomers, it results in the formation of optically inactive racemic mixture.
Question 7.
Explain the action of alcoholic $\mathrm{KOH}$ with 2-bromobutanc.
Answer:

According to Saytzcff's rule, when 2-bromobutanc reacts with alcoholic KOK, yields a mixture of olefins in different amounts.
(ii) In a dehydrohalogenation reaction, the preferred product is that alkene which has more number of alkyl groups attached to the doubly bonded carbon alkene.
Question 8.
Mention the uses of chloroform.
Answer:
- Chloroform is used as a solvent in pharmaceutical industry.
- It is used for producing pesticides and drugs.
- It is used as an anaesthetic.
Question 9.
What are the uses of carbon tetrachioride?
Answer:
- Carbon tetrachioride in used as a dry cleaning agent.
- It is used as a solvent for oils, fats and waxes.
- As the vapours of $\mathrm{CCl}_4$ is non-combustible, it is used under the name pyrene for extinguishing the fire caused by oil (or) petrol.
Question 10.
What are ogranometallic compounds? Give one example. Explain the nature of carbon-metal bond.

Answer:
- Organometallic compounds are organic compounds in which there is a direct carbon-metal bond.
- Example : $\mathrm{CH}_3 \mathrm{MgI}$ methyl magnesium iodide.
- The carbon-magnesium bond in Grignard reagent is covalent but highly polar. The carbon atom is more electronegative than magnesium. Hence, the carbon atom has partial negative charge and magnesium atom has a partial positive charge.

Question 11.
How would you prepare acetic acid from methyl magnesium iodide?
Answer:
Solid carbon dioxide reacts with grignard reagent to form addition product which on hydrolysis yields acetic acid.

Question 12 .
Explain the nature of $\mathrm{C}-\mathrm{X}$ bond in haloarenes and its resonance structure.
Answer:
1. In haloarenes, the carbon atom is $\mathrm{sp}^2$ hybridised. The $\mathrm{sp}^2$ hybridised orbitais arc shorter and holds the electron pair bond more.
2. Halogen atom contains p-orbital with lone pair of electrons which interacts with $\pi$-orbitaIs of berizene ring to form extended conjugated system of $\pi$ - orbitals.
3. The delocalisation of these electrons give double bond character to $\mathrm{C}-\mathrm{X}$ bond. The resonance structure of halobenzene are given as:

Question 13.
Compare the bond length $\mathrm{C}-\mathrm{X}$ in haloarenes and $\mathrm{C}-\mathrm{X}$ in haloalkanes.
Answer:
1. Due to this double bond character of $\mathrm{C}-\mathrm{X}$ bond in haloarenes, the $\mathrm{C}-\mathrm{X}$ bond length is shorter length and stronger than in haloalkanes.
2. Example:

Question 14.
What are the uses of chlorobenzene?
Answer:
- Chiorobenzene is used in the manufacture of pesticides like DDT.
- It is used as high boiling solvent in organic synthesis.
- It is used as a fibre - swelling agent in textile processing.
Question 15 .
What are polyhalogen compounds? Give its types with example.
Answer:
1. Carbon compounds containing more than one halogen atom are called polyhalogen compounds.
2. They are classified as
o gem dihalides
- Vicinal dihalides.
(a) Gem dihalide:
In this compound, two halogen atoms are attached to one carbon atom.
e.g, $\mathrm{CH}_3 \mathrm{CHCl}_2$ - ethylidene chloride.
(b) Vicinal dihalide:
In this compound, two halogen atoms are attached to two adjacent carbon atoms.

Question 16.
Give two examples for -
1. gem dihalide
2. vicinal dihalide.
Answer:
1. Gem dihalides:

2. Vicinal dihalides: 

Question 17.
Explain two methods of preparation of ethylene diehioride.
Answer:
1. Addition of $\mathrm{Cl}_2$ to Ethylene:

$\text { 2. Action of } \mathrm{PCl}_5 \text { on Ethylene glycol: }$

Question 18.
How would you distinguish gern-dihalides and iinal dihalides?
Answer:
(i) Gem-dihalides on hydrolysis with aqueous $\mathrm{KOH}$ gives an aldehyde or a ketone whereas vicinal dihalides on hydrolysis with aqueous $\mathrm{KOH}$ give glycols.

The above reaction can be used to distinguish between gem-dihalides and vicinal dihalides.
Question 19.
Explain the action of metallic zinc with -
(i) Ethylidene dichioride
(ii) Ethylene dichloridc.
Answer:

(i)

(ii)

Question 20 .
What happens when alcoholic $\mathrm{KOH}$ is treated with
(i) Ethylidene dichioride
(ii) Ethylene dich I onde?
Answer:
(i) Gem-dihalides and vicinal dihalides both on treatment with alcoholic $\mathrm{KOH}$ give alkynes.

(ii)

Question 21.
What are the uses of methylene chloride?
Answer:
Methylene chloride is used as:
- Aerosol spray propellant.
- Solvent in paint remover.
- Process solvent in the manufacture of drugs.
- A metal cleaning agent.
Question 22 .
Explain the laboratory preparation of chloroform.
Answer:
Haloform reaction:
Chloroform is prepared in the laboratory by the reaction between ethyl alcohol with bleaching powder followed by the distillation of the final product chloroform. Bleaching powder acts as a source of chlorine and calcium hydroxide. The reaction take place in 3 steps.
Step 1:
Oxidation-

Step 2:
Chlorination-

Step 3:
Hydrolysis-

Question 23.
What is chloropicrin? How is it obtained? Mention its uses.
Answer:
1. Chioropicrin is $\mathrm{CCl}_3 \mathrm{NO}_2$.
2. Chloroform reacts with nitric acid to form chioropicrin (trichioro-nitromethane):

3. Chioropicrin is used as an insecticide and soil sterilising agent.
Question 24.
What are the uses of freons?
Answer:
- Freons are used as refrigerants in refrigerators and air conditioners.
- It is used as a propellant for foams and aerosols.
- It is used as a propellant for foams to spray out deodorants, shaving creams and insecticides.
Question 25.
What is DDT? How is it prepared'?
Answer:
(i) $\mathrm{DDT}$ is p, p'-dichloro-diphenyi-trichloroethane
(ii) DDT can be prepared by heating a mixture of chloro benzene with chlorai in the presence of conc. $\mathrm{H}_2 \mathrm{SO}_4$

(iii)

Question 26.
Mention the uses of DDT.
Answer:
- $\mathrm{DDT}$ is used lo control certain insects which carries diseases like malaria and yellow fever.
- It is used in farms to control some agricultural pests.
- It is used in building construction as pest control agent.
- It is used to kill certain kind of insects like housefly and mosquitoes due to its high and specific toxicity.
Question 27.
Write the equations for the preparation of I-iodobutane from:
(i) 1 -butanol
(ii) 1 -chiorobutane
(iii) but- 1-ene
Answer:

(i)

(ii)

(iii)

Question 28.
Explain why:
1. the dipole moment of chiorobenzene is lower than that of cyclohexyl chloride?
2. alkyl halides though polar, are immiscible with water?
3. Gringard reagents should be prepared under anhydrous conditions?
Answer:
1. Chlorobenzene is stabilised by resonance and there is negative charge on ' $\mathrm{Cl}$ ' in 3 out of 5 resonating structures, therefore it has a lower dipole moment than cyclohexyl chloride in which there is no such negative charge.
2. Alkyl halides cannot form $\mathrm{H}$-bond with water and cannot break $\mathrm{H}$-bonds between water molecules, therefore they are insoluble in water.
3. Grignard reagents react with $\mathrm{H}_2 \mathrm{O}$ to form alkanes, therefore they are prepared under anhydrous conditions.
Question 29.
Explain as to why haloarenes arc much less reactive than haloalkanes towards nucleophilic substitution reactions?
Answer:
Haloarenes are much less reactive than haloalkanes towards nucleophilic substitution reactions due to the following reasons:
1. Resonance effect:
In haloarenes the electron pair on the halogen atom is in conjugation with the $\pi$-electrons of the ring and the following resonating structures are possible. $\mathrm{C}-\mathrm{Cl}$ bond acquires a partial double bond character due to
resonance. As a result, the bond cleavage in haloarenes is difficult than in case of haloalkanes and therefore they are less reactive towards nucleophilic substitution reactions.

2. The $\mathrm{C}-\mathrm{Cl}$ bond length in haloalkanes is $177 \mathrm{pm}$ while in haloarenes it is $169 \mathrm{pm}$. Since it is difficult to break shorter bond than a longer bond. Therefore, haloarenes are less reactive than haloalkanes towards nucleophilic substitution reactions.
Question 30 .
Do the following conversions:
(i) Methyl bromide to acetone
(ii) Benzyl alcohol to 2-phenylacetic acid
Answer:

(i)

(ii)

Question 31.
Give reasons for the following:
1. Ethyl iodide undergoes $\mathrm{S}_{N^2}$ reactions faster than ethyl bromide.
2. ( $\pm$) 2-Butanol is optically inactive.
3. C-X bond length in halobenzene is smaller than $\mathrm{C}-\mathrm{X}$ bond length in $\mathrm{CH}_3-\mathrm{X}$.
Answer:
1. Because in ethyl iodide, iodide being the best leaving group among all the halide ions. Rate of $\mathrm{S}_{\mathrm{N}^2}$ reaction ability of leaving group.
$\text { 2. ( } \pm \text { ) 2-hutanol is a racemic mixture which is optically inactive due to the external compensation. }$
3. Due to resonance in halobenzene, it has a smaller bond length value as compared to $\mathrm{CH}_3-\mathrm{X}$.
Question 32 .
Write the structure of diphenyl. How is it prepared from chlorobcnzene?

Answer:

5 Marks Question And Answers
Question 1 .
Explain the classification of organic compounds with example.
Answer:

Question 2.
Explain $\mathrm{S}_{\mathrm{N}^2}$ mechanism with suitable examples.
Answer:
- $\mathrm{S}_{\mathrm{N}^2}$ reaction means bimolecular nucleophilic substitution reaction of second order.
- This reaction involves the formation of a transition state in which both the reactant molecules are partially bonded to each other. The attack of nucleophile occurs from the back side.
- The carbon at which substitution occurs has inverted configuration during the course of reaction just as an umbrella has the tendency to invert in a wind-storm. This inversion of configuration is called walden inversion.

Question 4.
Explain $\mathrm{E}_2$ reaction mechanism with a suitable example.
Answer:
- $\mathrm{E}_2$ reaction stands bimolecular elimination reaction of second order. The rate of $\mathrm{E}_2$ reaction depends on the concentration of alkyl halide and the base.
- Primary alkyl halide undergoes this reaction in the presence of alcoholic $\mathrm{KOH}$.
- It is a one step process in which the abstraction of the proton from the 3 carbon atom and expulsion of halide from the $\mathrm{x}$ carbon atom occur simultaneously.
- The mechanism that follows is shown below:

Question 5.
Describe $E_1$ reaction mechanism with a suitable example.
Answer:
1. $E_1$ stands for unimolecular elimination reaction of first order.
2. Tertiary alkyl halides undergoes elimination reaction in the presence of alcoholic $\mathrm{KOH}$.
3. It takes place in two steps.
4. Step 1.
Heterolytic fission to yield a carbocation:

5. Step 2.
Elimination of a proton from the fl-carbon to produce an alkene:

Question 6.
Starting from methyl magnesium iodide how would you prepare -
1. Ethanol
2. 2-propanol
3. Tert-butyl alcohol.
Answer:
1. Ethanol:
Formaldehyde reacts with $\mathrm{CH}_3 \mathrm{MgI}$ to give an addition product which on hydrolysis yields ethanol.

2. 2-Propanol :
Acetaldehyde react with $\mathrm{CH}_3 \mathrm{MgI}$ to give an addition product which on hydrolysis yields 2-propanol.

Question 7.
Starting from methyl magnesium iodide, how would you prepare -
1. Ethyl methyl ether
2. methyl cyanide
3. methane.
Answer:
1. Ethyl methyl ether:
Lower halogenated ether reacts with grignard reagent to form higher ether.

2. Methyl cyanide:
Grignard reagent reacts 4rith cyanogen chloride to form alkyl cyanide.

3. Methane:
Grignard reagent reacts with waler to give methane as product.

Question 8.
Describe electrophilic substitution reaction of chiorohenzene with equations.
Answer:

(i)

(ii)

(iii)

(iv)

Question 9.
An organic compound (A) of molecular formula $\mathrm{C}_3 \mathrm{H}_6$ react with $\mathrm{HBr}$ in the presence of peroxide to give $\mathrm{C}_3 \mathrm{H}_7 \mathrm{Br}$ as (B) (B) on reaction with aqueous $\mathrm{KOH}$ gives (C) with molecular formula $\mathrm{C}_3 \mathrm{H}_8 \mathrm{O}$. Identify (A) (B) and (C)
Answer:
1. An organic compound (A) of molecular formula $\mathrm{C}_3 \mathrm{H}_6$ is $\mathrm{CH}_3-\mathrm{CH}=\mathrm{CH}_2$, Propene
2. Propene (A) reacts ith $\mathrm{HRr}$ in the presence of peroxide to give 1-bromopropane $\mathrm{CH}_3-\mathrm{CH}_2-\mathrm{CH}_2 \mathrm{Br}$ as (B).

3. 1-Bromopropane on reaction with aqueous $\mathrm{KOH}$ undergoes hydrolysis to give Propan- 1-ol. $\mathrm{CH}_3$ $\mathrm{CH}_2-\mathrm{CH}_2 \mathrm{OH}$ as (C)

Question 10 .
An organic compound (A) of molecular formula $\mathrm{C}_2 \mathrm{H}_6 \mathrm{O}$ reacts with thionyl chloride in the presence of pyridine gives (B) $\mathrm{C}_2 \mathrm{H}_5 \mathrm{Cl}$. (B) on reaction with alcoholic $\mathrm{KOH}$ gives (C), $\mathrm{C}_2 \mathrm{H}_4$. (C) on treatmeni with $\mathrm{Cl}_2$ gives $\mathrm{C}_2 \mathrm{H}_4 \mathrm{Cl}_2$ as (D). Identify (A) (B) (C) (D) and explain the reaction.
Answer:
1. An organic compound (A) of molecular formula $\mathrm{C}_2 \mathrm{H}_6 \mathrm{O}$ is Ethanol $\mathrm{CH}_3-\mathrm{CH}_2 \mathrm{OH}$.
2. Ethanol reacts with thionyl chloride in the presence of pyridine to give $\mathrm{CH}_3-\mathrm{CH}_2 \mathrm{Cl}$ (B) as product.

3. Ethyl chloride on treatment with alcoholic $\mathrm{KOH}$, undergoes dehydrohalogenation to give $\mathrm{C}_2 \mathrm{H}_4$, ethylene (C) as the product.

$\text { 4. Ethylene on reaction with } \mathrm{Cl}_2 \text { yield ethylene dichioride as (D) as the product. }$

Question 11.
The simplest aromatic hydrocarbon $\mathrm{C}_6 \mathrm{H}_6$ reacts (B) on treatment with sodium hydroxide will $\left(\mathrm{C}_6 \mathrm{H}_5 \mathrm{OH}\right)$, Phenol, (C) as the product. Also $\mathrm{Cl}_2$ to give (A) which on reaction with sodium hydroxide gives (B).(B) of molecular formula $\mathrm{C}_6 \mathrm{H}_6 \mathrm{O}$. (B) on treatment with ammonia will give $\mathrm{C}_6 \mathrm{H}_7 \mathrm{~N}$ as D. Identify (A), (B), (C), and explain the reactions involved.
Answer:
1. The aromatic hydrocarbon (B) is Benzene, $\mathrm{C}_6 \mathrm{H}_6$.
2. Benzene reacts with $\mathrm{Cl}$, to give chiorobenzene $\left(\mathrm{C}_6 \mathrm{H}_5 \mathrm{Cl}\right)$, as (B) as the product.

$\text { 3. Chiorobenzene (B) reacts with sodium hydroxide to give }\left(\mathrm{C}_6 \mathrm{H}_5 \mathrm{OH}\right) \text { phenol, (C) as the product. }$

$\text { 4. Chiorobenzene reacts with ammonia to give Aniline, } \mathrm{C}_6 \mathrm{H}_5 \mathrm{NH}_2 \text { (D) as the product. }$

Question 12.
An organic compound (A) of molecular formula $\mathrm{C}_2 \mathrm{H}_2$ reacts with $\mathrm{HCl}$ to give $\mathrm{C}_2 \mathrm{H}_4 \mathrm{Cl}_2$ as (B). (B) on reaction with aqueous $\mathrm{KOH}$ will give $\mathrm{C}_2 \mathrm{H}_4 \mathrm{O}$ as (C) Identify (A), (B), (C) and explain the reactions involved.

Answer:
1. An organic compound (A) of molecular formula $\mathrm{C}_2 \mathrm{H}_2$ is $\mathrm{CH} \equiv \mathrm{CH}$ (Acetylene)
2. Acetylene (A) reacts with $\mathrm{HCl}$ to give ethylene dichioride (B) as the product.

$\text { 3. Ethylidene dichioride on reaction with aqueous } \mathrm{KOH} \text { will give acetaldehyde, } \bigcirc \text { as the product. }$

Question 13.
Two isomers of formula $\mathrm{C}_4 \mathrm{H}_9 \mathrm{Br}$ are (A) and $\mathrm{B}$. (A) on reaction with alcoholic $\mathrm{KOH}$ gives of molecular formula $\mathrm{C}_8 \mathrm{H}_8$ by $\mathrm{E}_1$ reaction. (B) on reaction with alcoholic $\mathrm{KOH}$ gives (D) and (E) as products by Saytzefi's rule. Idcnti' A, B, C, D, E.
Answer:

$\text { 1. } \mathrm{C}_4 \mathrm{H}_9 \mathrm{Br} \text { : Two isomers may be there: }$

Tert butyl bromide and 

$\text { 2. (A) on reaction with alcoholic } \mathrm{KOH} \text { gives iso butylene (C) as the product. }$

3. 2-bromobutane (B) on reaction with alcoholic $\mathrm{KOH}$ follows Saytzeff s rule to give a mixture of olefins in different amounts.

Question 14.
A simple aromatic hydrocarbon (A) reacts with $\mathrm{Cl}_2$ to give (B) of molecular formula $\mathrm{C}_6 \mathrm{H}_5 \mathrm{Cl}$. (B) on reaction with ethyl chloride along with sodium metal gives (C) of formula $\mathrm{C}_8 \mathrm{H}_{10}$. (C) alone reacts with $\mathrm{Na}$ metal in the presence of ether to give (D) $\mathrm{C}_{12} \mathrm{H}_{10}$. Identify (A) (B) (C) \& (D)
Answer:
1. The simple aromatic hydrocarbon is $\mathrm{C}_6 \mathrm{H}_6$. Benzene (A)
2. Benzene reacts with $\mathrm{Cl}_2$ to give chiorobenzene.

3. Chiorobenzene reacts with ethyl chloride to form ethyl benzene, (C) as the product 

$\text { 4. Chiorobenzene on reaction } \mathrm{Na} \text { metal gives Biphenyl compound ( }) \text { as the product. }$

Question 15 .
An organic compound (A) of molecular formula $\mathrm{CH}_2 \mathrm{O}$ reacts with methyl magnesium iodide followed by
acid hydrolysis to give (B) of moLecular formula $\mathrm{C}_2 \mathrm{H}_6 \mathrm{O}$. (B) on reaction with $\mathrm{PCl}_5$ gives (B). (C) on reaction with alcoholic KOK gives (D) an alkene as the product. Identif' (A) (B) (C) (D) and explain the reactions involved.
Answer:
1. (A) of molecular formula $\mathrm{CH}_2 \mathrm{O}$ is identified as $\mathrm{HCHO}$, formaldehyde.
2. Formaldehyde reacts with $\mathrm{CH}_3 \mathrm{MgI}$ followed by hydrolysis to give ethanol, $\mathrm{CH}_3-\mathrm{CH}_2 \mathrm{OH} \mathrm{B}$ as the product.

3. Ethanol (B) reacts with $\mathrm{PCl}_5$ to give $\mathrm{C}_2 \mathrm{H}_5 \mathrm{Cl}$, Ethyl chloride (C as the product.
4. $\mathrm{CH}_3-\mathrm{CH}_2 \mathrm{Cl} @$ on reaction with alcoholic $\mathrm{KOH}$ undergoes dehydrohalogenation to give ethylene $\mathrm{CH}_2=\mathrm{CH}_3$ (D) as the product.