Text Book Back Questions and Answers - Chapter 12 - Carbonyl Compounds and Carboxylic Acids - 12th Chemistry Guide Samacheer Kalvi Solutions

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Carbonyl Compounds and Carboxylic Acids
Text Book Evaluation
Multiple ChoiceQuestions
Question 1.
The correct structure of the product 'A' formed in the reaction

Answer:

Question 2.
The formation of cyanohydrin from acetone is an example of
(a) nucleophilic substitution
(b) electrophilic substitution
(c) electrophilic addition
(d) Nucleophilic addition
Answer:
(d) Nucleophilic addition
Question 3.
Reaction of acetone with one of the following reagents involves nucleophilic addition followed by elimination of water. The reagent is
(a) Grignard reagent
(b) $\mathrm{Sn} / \mathrm{HCl}$
(c) hydrazine in presence of slightly acidic solution
(d) hydrocyanic acid
Answer:
(c) hydrazine in presence of slightly acidic solution
Question 4.
In the following reaction,

Product ' $\mathrm{X}$ ' will not give
(a) Tollen's test
(b) Victor meyer test
(c) Iodoform test
(d) Fehiing solution test
Answer:
(b) Victor meyer test
Hint:

(x) reduces tollens reagent and Fehiing solution aind it also answers iodoform test.
Question 5 .
In the following reaction,

(a) Formaldelyde
(b) diacetoneammonia
(c) hexamethylenetetraamlne
(d) oxime
Answer:
(c) hexamethylenetetraamlne
Hint:
$
\begin{aligned}
& \mathrm{X}-\mathrm{HCHO} \\
& \mathrm{Y}-\left(\mathrm{CH}_2\right)_6 \mathrm{~N}_4
\end{aligned}
$
Question 6.
Predict the product $\mathrm{Z}$ in the following series of reactions

(a) $\left(\mathrm{CH}_3\right)_2 \mathrm{C}(\mathrm{OH}) \mathrm{C}_6 \mathrm{H}_5$
(b) $\mathrm{CH}_3 \mathrm{CH}(\mathrm{OH}) \mathrm{C}_6 \mathrm{H}_5$
(c) $\mathrm{CH}_3 \mathrm{CH}(\mathrm{OH}) \mathrm{CH}_2-\mathrm{CH}_3$

Answer:
(a) $\left(\mathrm{CH}_3\right)_2 \mathrm{C}(\mathrm{OH}) \mathrm{C}_6 \mathrm{H}_5$
Hint:

Question 7.
Assertion: 2, 2-dirnethyl propanoic acid does not give HVZ reaction.
Reason: $2-2$, dimethyl propanoic acid does, not have - a hydrogen atom
(a) if both assertion and reason are true and reason is the correct explanation of assertion.
(b) if both assertion and reason are true but reason is not the correct explanation of assertion.
(c) assertion is true but reason is false
(d) both assertion and reason are false
Answer:
(a) if both assertion and reason are true and reason is the correct explanation of assertion.
Hint:

Question 8.
Which of the following represents the correct order of acidity in the given compounds
(a) $\mathrm{FCH}_2 \mathrm{COOH}>\mathrm{CH}_3 \mathrm{COOH}>\mathrm{BrCH}_2 \mathrm{COOH}>\mathrm{CICH}_2 \mathrm{COOH}$
(b) $\mathrm{FCH}_2 \mathrm{COOH}>\mathrm{CICH}_2 \mathrm{COOH}>\mathrm{BrCH}_2 \mathrm{COOH}>\mathrm{CH}_3 \mathrm{COOH}$
(c) $\mathrm{CH}_3 \mathrm{COOH}>\mathrm{CICH}_2 \mathrm{COOH}>\mathrm{FCH}_2 \mathrm{COOH}>\mathrm{Br}-\mathrm{CH}_2 \mathrm{COOH}$
(d) $\mathrm{ClCH}_2 \mathrm{COOH}>\mathrm{CH}_3 \mathrm{COOH}>\mathrm{BrCH}_2 \mathrm{COOH}>\mathrm{ICH}_2 \mathrm{COOH}$
Hint.
$-\mathrm{I}$ effect increases the acidity. If electronegativity is high, $-\mathrm{I}$ effect is also high.
Question 9.
Benzoic acid

(a) anilinium chloride
(b) $\mathrm{O}$ - nitro aniline
(c) benzene diazonium chloride
(d) $\mathrm{m}$ - nitro benzoic acid
Answer:
(c) benzene diazonium chloride
Hint:

Question 10 .
Ethanoic acid
$
\stackrel{\mathrm{P} / \mathrm{Br}_2}{\longrightarrow} 2
$
2 - bromoethanoic acid. This reaction is called
(a) Finkeistein reaction
(b) Haloform reaction
(c) Hell - Volhard - Zelinsky reaction
(d) none of these
Answer:
(c) Hell-Volhard - Zelinsky reaction
Question 11.

(a) acetylchloride
(b) chioro acetic acid
(c) $\alpha$-chiorocyano ethanoic acid
(d) none of these
Hint:

Question 12 .
Which one of the following reduces tollens reagent
(a) formic acid
(b) acetic acid
(c) benzophenone
(d) none of these
Answer:
(a) formic acid
Hint:

Question 13 .

Answer:

Hint:

Question 14 .
The TUPAC name of

(a) but-3-enoicacid
(b) but 1 - ene -4 - oicacid
(c) but 2 - ene-1-oic acid
(d) but-3-ene-1-oicacid
Answer:
(a) but - 3 - enoicacid
Hint:

Question 15 .
Identify the product formed in the reaction

Answer:

Hint:

Group is reduced to $\mathrm{CH}_2$ - (Wolff - Kishner reduction)
Question 16.
In which case chiral carbon is not generated by reaction with $\mathrm{HCN}$

Answer:

Hint:

Question 17.
Assertion: $\mathrm{p}-\mathrm{N}, \mathrm{N}-$ dimethyl aminobenzaldehyde undergoes benzoin condensation Reason: The aldehydic (- $\mathrm{CHO})$ group is meta directing
(a) if both assertion and reason are true and reason is the correct explanation of assertion.
(b) if both assertion and reason are true but reason is not the correct explanation of assertion.
(c) assertion is true but reason is false
(d) both assertion and reason are false
Answer:
(b) if both assertion and reason are true but reason is not the correct explanation of assertion.
Hint:

Question 18 .
Which one of the following reaction is an example of disproportionation reaction
(a) Aldol condensation
(b) cannizaro reaction
(c) Benzoin condensation
(d) none of these
Answer:
(b) cannizaro reaction
Hint:

Question 19.
Which one of the following undergoes reaction with $50 \%$ sodium hydroxide solution to give the corresponding alcohol and acid ...........
(a) Phenylmethanal
(b) ethanal
(c) ethanol
(d) methanol
Answer:
(a) Phenylmethanal
Question 20.
The reagent used to distinguish between acetaldehyde and benzaldehyde is
(a) Tollens reagent
(b) Fehling's solution
(c) 2,4-dinitrophenyl hydrazine
(d) semicarbazide
Answer:
(b) Fehling's solution
Question 21.
Phenyl methanal is reacted with concentrated $\mathrm{NaOH}$ to give two products $\mathrm{X}$ and $\mathrm{Y}$. $\mathrm{X}$ reacts with metallic sodium to liberate hydrogen $\mathrm{X}$ and $\mathrm{Y}$ are
(a) sodiumbenzoate and phenol
(b) Sodium benzoate and phenyl methanol
(c) phenyl methanol and sodium benzoate
(d) none of these
Answer:
(c) phenyl methanol and sodium benzoate
Hint:

Question 22.
In which of the following reactions new carbon - carbon bond is not formed?
(a) Aldol condensation
(b) Friedel craft reaction
(c) Kolbe's reaction
(d) Wolf kishner reduction
Answer:
(d) Wolf kishner reduction
Question 23.
An alkene "A" on reaction with $\mathrm{O}_3$ and $\mathrm{Zn}-\mathrm{H}_2 \mathrm{O}$ gives propanone and ethanol in equimolar ratio. Addition of $\mathrm{HCl}$ to alkene "A" gives " $\mathrm{B}$ " as the major product. The structure of product " $\mathrm{B}$ " is

Answer:

Hint:

Question 24.
Carboxylic acids have higher boiling points than aldehydes, ketones and even alcohols of comparable molecular mass. It is due to their
(a) more extensive association of carboxylic acid via van der Waals force of attraction
(b) formation of carboxylate ion
(c) formation of intramolecular $\mathrm{H}$ - bonding
(d) formation of intermolecular $\mathrm{H}$ - bonding
Answer:
(d) formation of intermolecular $\mathrm{H}$ - bonding
Question 25.
Of the following, which is the product formed when cyclohexanone undergoes aldol condensation followed by heating?

Answer:

II. Answer the following questions.
Question 1.
How is propanoic acid is prepared starting from
1. an alcohol
2. an alkyihalide
3. an alkene
Preparation of propanoic acid from,
Answer:
1. Alcohol:

2. Alkylhalide:

3. Alkene:

Question 2.
A Compound (A) with molecular formula $\mathrm{C}_2 \mathrm{H}_3 \mathrm{~N}$ on acid hydrolysis gives(B) which reacts with thionyichioride to give compound(C). Benzene reacts with compound (C) in presence of anhydrous $\mathrm{AlCl}_3$ to give compound (C). Compound (C) on reduction with gives (D). Identify (A), (B), (C) and D. Write the equations.
Answer:
1. Compound (A) with molecular formula $\mathrm{C}_2 \mathrm{H}_3 \mathrm{~N}$ is methyl cyanide. $\left(\mathrm{CH}_3 \mathrm{CN}\right)$
2. Methyl cyanide (A) on hydrolysis gives acetic acid (B)

3. Acetic acid (B) with thionyl chloride to give acetyl chloride (C)

4. Benzene reacts with acetyl chloride (C) in the presence of anhydrous $\mathrm{AlCl}_3$ to give acetophenone (D)

5. Acetyl chloride (C) on reduced in the presence of $\mathrm{Pd} / \mathrm{H}_2$ and Barium sulphate, to gives acetaldehyde (E).

Question 3.
Identify $\mathrm{X}$ and $\mathrm{Y}$
$
\mathrm{CH}_3 \mathrm{COCH}_2 \mathrm{CH}_2 \mathrm{COOC}_2 \mathrm{H}_5 \stackrel{\mathrm{CH}_3 \mathrm{MgBr}}{\longrightarrow} \mathrm{X} \stackrel{\mathrm{H}_3 \mathrm{O}^{+}}{\longrightarrow} \mathrm{Y}
$
Answer:

Question 4.
Identify $\mathrm{A}, \mathrm{B}$ and $\mathrm{C}$

 

Answer:

Question 5.
A hydrocarbon $\mathrm{A}$ (molecular formula $\mathrm{C}_8 \mathrm{H}_{10}$ ) on ozonolysis gives $\mathrm{B}\left(\mathrm{C}_4 \mathrm{H}_6 \mathrm{O}_2\right.$ ) only. Compound $\mathrm{C}\left(\mathrm{C}_3 \mathrm{H}_5 \mathrm{Br}\right)$ on treatment with magnesium in dry ether gives (D) which on treatment with $\mathrm{CO}_2$ followed by acidification gives (B). Identify A, B, C and D.
Answer:
1. Molecular formula $\mathrm{C}_8 \mathrm{H}_{10}$ is 1,2 -dicyclopropylethyne.

2. 1,2 - dicyclo propyl ethyne (A) on ozonolysis to give cyclo propyl carboxylic acid (B)

3. Compound $\mathrm{C}_3 \mathrm{H}_5 \mathrm{Br}$ is Bromo cyclo propane (C), which on reacts with $\mathrm{Mg}$ in dry ether gives Grignard reagent (D) which on treatment with $\mathrm{CO}_2$ followed by acidification gives cyclo propyl carboxylic acid (B).

Question 6.
Identify $\mathrm{A}, \mathrm{B}, \mathrm{C}$ and $\mathrm{D}$

Answer:

Question 7.
An alkene (A) on ozonolysis gives propanone and aldehyde (E). When (B) is oxidised (C) is obtained. (C) is treated with $\mathrm{Br}_2$ JP gives (D) which on hydrolysis gives (E). When propanone is treated with $\mathrm{HCN}$ followed by hydrolysis gives (F). Identify A, B, C, D and $\mathrm{E}$ and $\mathrm{F}$.
Answer:
1. 2- methyl - but - 2 - ene (A) on ozonolysis gives propanone and acetaldehyde (B)

2. Acetaldehyde $(\mathrm{B})$ is oxidised to give acetic acid (C), which on further treated with $\mathrm{Br}_2 / \mathrm{P}$ give monobromo acetyl bromide (D) which on hydrolysis gives monobromo acetic acid (E).

$\text { 3. Propanone is treated with } \mathrm{HCN} \text { followed by hydrolysis to gives } 2-\text { methyl - } 2 \text { - hydorxy propanoic acid (F) }$

Question 8
How will you convert benzaldehyde into the following compounds?
1. benzophenone
2. benzoic acid
3. 2-hydroxyphenylaceticacid.
Answer:
1. conversion of benzaldehyde into benzophenone.

2. conversion of benzaldehyde into benzoic acid.

3. conversion of benzaldehyde into 2 -hydroxy phenyl acetic acid.

Question 9.
What is the action of $\mathrm{HCN}$ on
1. propanone
2. 2,4-dichiorobenzaldehyde.
Answer:
1. Propanone reacts with $\mathrm{HCN}$.

$\text { 2. 2, 4-dichlorobenzaldehyde reacts with } \mathrm{HCN} \text {. }$

Question 10 .
A carbonyl compound $A$ having molecular formula $\mathrm{C}_5 \mathrm{H}_{10} \mathrm{O}$ forms crystalline precipitate with sodium bisuiphate and gives positive iodoform test. A does not reduce Fehling solution. Identify A.

Answer:

1.

2. Pentan $-2-$ one gives positive iodoform test, but it does not reduce Fehling's solution.
3. Hence carbonyl compound $\mathrm{A}$ having molecular formula $\mathrm{C}_5 \mathrm{H}_{10} \mathrm{O}$ is pentan $-2-$ one.

Question 11.
Write the structure of the major product of the aldol condensation of benzaldehyde with acetone.
Answer:
Step 1:

Step 2:

Step 3:

Step 4:

Question 12 .
How are the following conversions effected
1. propanal into butanone
2. Hex $-3-$ yne into hexan -3 - one.
3. phenylmethanal into benzoic acid
4. phenylmethanal into benzoin
Answer:
1. propanal into butanone

2. Hex-3-yne into hexan -3 - one

3. phenylmethanal into benzoic acid

4. phenylmethanal into benzoin

Question 13.
Complete the following reaction.

Answer:

Overall reaction:

Question 14.
Identify A, B and C

Answer:

Question 15 .
When ketones are undergo oxidation, the $\mathrm{C}-\mathrm{C}$ bond Is cleaved. When a strong oxidising agent is used to oxidise 2,5-dimethyl hexan -3 - one mention the products with their names.
Answer:

Question 16.
How will you convert following conversion?
1. Acetic acid into acetic anhydride
2. Methyl acetate into ethyl acetate
3. Methyl acetate into acetamide
4. Acetyl chloride into acetophenone
5. Sodium acetate into ethane
6. Ethanal into lactic acid
7. Toluene into benzoic acid
8. Benzaldehyde into malachite green
9. Benzaldehyde into Cinnamic acid
10. Ethyne into acetaldehyde
Answer:
1. Conversion of Acetic acid into acetic anhydride

2. Conversion of Methyl cyanate into acetamide.

3. Conversion of Methyl cyanate into acetamide.

4. Conversion of Acetyl chloride into acetophenone.

5. Conversion of Sodium acetate into ethane.

6. Conversion of Ethanal into lactic acid.

7. Conversion of Toluene into benzoic acid.

8. Conversion of Benzaldehyde into malachite green.

9. Conversion of benzaldehyde into cinnamic acid

10. Conversion of Ethyne into acetaldehyde.

Question 1.
Write the IUPAC name for the following compound.

(i)

(ii) $\left(\mathrm{CH}_3\right)_2 \mathrm{C}=\mathrm{CHCOCH}_3$
(iii)

(iv) $\left(\mathrm{CH}_3\right)_2 \mathrm{C}(\mathrm{OH}) \mathrm{CH}_2 \mathrm{CHO}$

Answer:

(i)

(ii)

(iii)

(iv)

Question 2.
Wrtie all possible structural isomers and position isomers for the ketone represented by the molecular formula $\mathrm{C}_5 \mathrm{H}_{10} \mathrm{O}$.
Answer:
Molecular formula $\mathrm{C}_5 \mathrm{H}_{10} \mathrm{O}$ exhibits following possible ketone structural isomers and position isomers.

Question 3.
What happens when the following alkenes are subjected to reductive ozonolysis.
1. propene
2. 1 - Butene
3. Isobutylene
Answer:
1. propene

2. 1 -Butene

3. Isobutylene

Question 4 .
What happens when n-propyl benzene is oxidised using $\mathrm{H}^{+} / \mathrm{KMnO}_4$ ?
Answer:
When $\mathrm{n}$ - propyl benzene is oxidised with $\mathrm{H}^{+} / \mathrm{KMnO}_4$ to gives benzoic acid.

Question 5.
How will you prepare benzoic acid using Crignard reagent.

Answer:
Preparation of benzoic acid using Grignard reagent:

Question 6.
Why acid anhydride are preferred to acyl chloride for carrying out acylation reactions?
Answer:
Acid anhydride are preferred to acyl chloride for carrying out acylation reactions. Because
1. Easily available
2. Cheap
3. Easy to prepare
4. Easily undergo acylation without irritating odours