Benzaldehyde, when heated with concentrated ${\rm{KOH}}$ solution, gives:

Mixture of ${{\rm{C}}_6}{{\rm{H}}_5}{\rm{COOK}}\,{\rm{\;and\;}}\,\,{{\rm{C}}_6}{{\rm{H}}_5}{\rm{C}}{{\rm{H}}_2}{\rm{OH}}$

${{\rm{C}}_6}{{\rm{H}}_5}{\rm{C}}{{\rm{H}}_2}{\rm{OH}}$

${{\rm{C}}_6}{{\rm{H}}_5}{\rm{COOH}}$

${{\rm{C}}_6}{{\rm{H}}_5}{\rm{COOK}}$

Identify A and B in the following reaction $\begin{array}{l} {\rm{C}}{{\rm{H}}_3} - {\rm{C}}{{\rm{H}}_3}\xleftarrow{B}{\rm{C}}{{\rm{H}}_3}{\rm{COOH}}\xrightarrow{A}{\rm{C}}{{\rm{H}}_3}{\rm{C}}{{\rm{H}}_2}{\rm{OH}}\\ \;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;{\rm{A}}\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;{\rm{B}} \end{array}$

${\rm{LiAl}}{{\rm{H}}_4}{\rm{HI}} + {\rm{red}}\;{\rm{ P}}$

${\rm{HI}} + {\rm{red}}\;{\rm{ PLiAl}}{{\rm{H}}_4}$

${\rm{Ni}}/\Delta {\rm{LiAl}}{{\rm{H}}_4}$

${\rm{Pd}} - {\rm{BaS}}{{\rm{O}}_4}{\rm{Zn}} + {\rm{HCl}}$

Chlorobenzene $\xrightarrow[X]{{{\rm{Reaction\;\;}}}}{\rm{\;Phenol\;}}\xrightarrow[Y]{{{\rm{Reaction\;\;}}}}$ Salicyladehyde $X\;and\;Y$ reactions are respectively……….

Fires rearrangement and Kolbe-Schmidt

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JEE • CHEMISTRY • ALDEHYDES & KETONES & CARBOXYLIC ACIDS

Aldehydes & ketones & carboxylic acids practice · Mixed difficulty

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These sets use single-correct-answer MCQs. They do not cover every JEE Main or JEE Advanced question format and are not full-length mock papers.

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151 Medium

151 of 255

Analyzing +4 | -1

Among the following, the most acidic is

View answer and explanation

Correct option: C

\mathrm{C}{\mathrm{l}_2}\mathrm{CHCOOH}

Option C (Cl2CHCOOH) is correct because the presence of more electron-withdrawing chlorine atoms closer to the carboxylic acid group increases acidity.

152 Easy

152 of 255

Understanding +4 | -1

Benzaldehyde, when heated with concentrated

\mathrm{KOH}

solution, gives:

View answer and explanation

Correct option: D

Mixture of

{\mathrm{C}_6}{\mathrm{H}_5}\mathrm{COOK}\,\mathrm{\;and\;}\,\,{\mathrm{C}_6}{\mathrm{H}_5}\mathrm{C}{\mathrm{H}_2}\mathrm{OH}

Option D is correct because benzaldehyde undergoes Cannizzaro reaction in the presence of concentrated KOH, yielding a mixture of potassium benzoate and benzyl alcohol.

153 Medium

153 of 255

Remembering +4 | -1

Acetone is used:

View answer and explanation

Correct option: D

All are correct

Option D (All are correct) is correct because acetone is used as a solvent, in nail polishes, and for storing acetylene under pressure.

154 Medium

154 of 255

Understanding +4 | -1

In which of the following reactions, both oxidized and reduced forms of the same compound are obtained?

View answer and explanation

Correct option: B

Cannizzaro reaction

Option B (Cannizzaro reaction) is correct because it involves the self-oxidation and reduction of an aldehyde without alpha-hydrogens.

155 Medium

155 of 255

Understanding +4 | -1

Identify A and B in the following reaction

\begin{array}{l} \mathrm{C}{\mathrm{H}_3} - \mathrm{C}{\mathrm{H}_3}\xleftarrow{B}\mathrm{C}{\mathrm{H}_3}\mathrm{COOH}\xrightarrow{A}\mathrm{C}{\mathrm{H}_3}\mathrm{C}{\mathrm{H}_2}\mathrm{OH}\\ \;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\mathrm{A}\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\mathrm{B} \end{array}

View answer and explanation

Correct option: C

\mathrm{LiAl}{\mathrm{H}_4}\mathrm{HI} + \mathrm{red}\;\mathrm{ P}

Option C (

\mathrm{LiAl}{\mathrm{H}_4}\mathrm{HI} + \mathrm{red}\;\mathrm{ P}

) is correct because

LiAlH_4

reduces carboxylic acid to alcohol, and HI/red P reduces it to alkane.

156 Easy

156 of 255

Understanding +4 | -1

Reaction of a carbonyl compound with one of the following reagents involves nucleophilic addition followed by elimination of water. The reagent is:

View answer and explanation

Correct option: D

Hydrazine in presence of feebly acidic solution

Option D (Hydrazine in presence of feebly acidic solution) is correct because hydrazine reacts with carbonyl compounds via nucleophilic addition followed by water elimination to form hydrazones.

157 Medium

157 of 255

Analyzing +4 | -1

Through which of the following reactions number of carbon atoms can be increased in the chain?

(i) Grignard reaction

(ii) Cannizzaro's reaction

(iii) Aldol condensation

(iv) HVZ reaction

Choose the correct option.

View answer and explanation

Correct option: A

Only (iii) and (i)

Option A is correct because Grignard reaction and Aldol condensation are carbon-carbon bond forming reactions, thus increasing the number of carbon atoms in the chain.

158 Medium

158 of 255

Analyzing +4 | -1

Assertion (A): Benzaldehyde is more reactive than ethanal towards nucleophilic attack.

Reason (R): Both benzaldehyde and acetaldehyde have alpha hydrogens.

View answer and explanation

Correct option: D

Both (A) and (R) are false

Option D is correct. Benzaldehyde is less reactive than ethanal towards nucleophilic attack due to steric hindrance, and benzaldehyde does not have alpha hydrogens.

159 Medium

159 of 255

Remembering +4 | -1

Benzaldehyde can be prepared from benzene by passing vapours of ____ and ____ in its solution in presence of catalyst mixture of aluminium chloride and cuprous chloride. The reaction is known is _____

View answer and explanation

Correct option: B

{CO}, {HCl}

, Gattermann-Koch reaction

Option B (

{CO}, {HCl}

, Gattermann-Koch reaction) is correct because the Gattermann-Koch reaction uses carbon monoxide and hydrochloric acid in the presence of a catalyst to convert benzene to benzaldehyde.

160 Medium

160 of 255

Remembering +4 | -1

Salol (phenyl salicylate ) is used as an:

View answer and explanation

Correct option: D

Intestinal antiseptic

Option D (Intestinal antiseptic) is correct because Salol (phenyl salicylate) is used as an intestinal antiseptic due to its ability to break down into salicylic acid and phenol in the intestines.

161 Medium

161 of 255

Analyzing +4 | -1

Statement I: Acetaldehyde cannot be prepared by the Rosenmund reduction.

Statement II: Formyl chloride is unstable at room temperature.

View answer and explanation

Correct option: D

Statement II is correct, Statement I is incorrect.

Statement II is correct, Statement I is incorrect because Rosenmund reduction cannot be used to prepare formaldehyde, not acetaldehyde, due to the instability of formyl chloride.

162 Medium

162 of 255

Understanding +4 | -1

Which of the following compound is least reactive towards hydrolysis?

View answer and explanation

Correct option: A

Acetamide

Option A (Acetamide) is correct because amides are generally less reactive towards hydrolysis compared to acid chlorides, anhydrides, and esters due to resonance stabilization.

163 Medium

163 of 255

Analyzing +4 | -1

2-pentanone and 3-petanone can be distinguished by

View answer and explanation

Correct option: C

Iodoform reaction

Option C (Iodoform reaction) is correct because 2-pentanone has a methyl ketone group (CH₃CO) that reacts with I₂/NaOH to give a positive iodoform test, while 3-pentanone does not.

164 Medium

164 of 255

Understanding +4 | -1

Which will not give acetamide (no heating) on reaction with ammonia?

View answer and explanation

Correct option: A

Acetic acid

Option A (Acetic acid) is correct because acetic acid reacts with ammonia to form ammonium acetate, which requires heating to form acetamide.

165 Hard

165 of 255

Understanding +4 | -1

Benzaldehyde reacts with excess of anhydrous ethyl alcohol in the presence of

HCl

, gives:

View answer and explanation

Correct option: C

{C_6}{H_5}CH{\left( {O{C_2}{H_5}} \right)_2}

Option C (

{C_6}{H_5}CH{\left( {O{C_2}{H_5}} \right)_2}

) is correct because benzaldehyde reacts with excess ethanol in the presence of HCl to form an acetal.

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166 Medium

166 of 255

Remembering +4 | -1

Rosenmund’s reduction is used for the preparation of

View answer and explanation

Correct option: B

Aldehyde

Option B (Aldehyde) is correct because Rosenmund's reduction is used for the preparation of aldehydes from acyl chlorides.

167 Medium

167 of 255

Understanding +4 | -1

The number of aldehyde isomers for

{C_4}{H_8}O

will be

View answer and explanation

Correct option: C

Option C (2) is correct because there are two aldehyde isomers for C4H8O: butanal and 2-methylpropanal.

168 Medium

168 of 255

Remembering +4 | -1

The elimination of

\mathrm{C}{\mathrm{O}_2}

from a carboxylic acid is known as:

View answer and explanation

Correct option: C

Decarboxylation

Option C (Decarboxylation) is correct because decarboxylation is the process of removing a carboxyl group (COOH) from a molecule, releasing carbon dioxide.

169 Medium

169 of 255

Analyzing +4 | -1

Formaldehyde and formic acid can be distinguished by:

View answer and explanation

Correct option: D

\mathrm{NaHC}{\mathrm{O}_3}

Option D (

\mathrm{NaHC}{\mathrm{O}_3}

) is correct because formic acid reacts with sodium bicarbonate to produce carbon dioxide gas, while formaldehyde does not.

170 Hard

170 of 255

Understanding +4 | -1

Chlorobenzene

\xrightarrow[X]{{\mathrm{Reaction\;\;}}}\mathrm{\;Phenol\;}\xrightarrow[Y]{{\mathrm{Reaction\;\;}}}

Salicyladehyde

X\;and\;Y

reactions are respectively……….

View answer and explanation

Correct option: C

Dow and Reimer-Tiemann

Option C is correct. Chlorobenzene is converted to phenol by Dow's process, and phenol is converted to salicylaldehyde by the Reimer-Tiemann reaction.

171 Medium

171 of 255

Application +4 | -1

0.759 g of a silver salt of a dibasic organic acid on ignition left 0.463 g metallic silver. The equivalent weight of acid is:

View answer and explanation

Correct option: A

Option A (70) is correct because the equivalent weight of the acid is calculated using the equivalent weights of the silver salt and silver.

172 Medium

172 of 255

Remembering +4 | -1

Ketones can be converted to alkanes directly on reaction with

View answer and explanation

Correct option: C

{HI} / {P}_4 / \Delta

Option C (

{HI} / {P}_4 / \Delta

) is correct because ketones can be directly converted to alkanes using HI and red phosphorus under heating conditions.

173 Medium

173 of 255

Analyzing +4 | -1

An organic compound is boiled with alcoholic potash. The product is cooled and acidified with HCl. A white solid separates out. The starting compound may be

View answer and explanation

Correct option: A

Ethyl benzoate

Option A (Ethyl benzoate) is correct because it undergoes saponification with alcoholic potash to form potassium benzoate, which upon acidification yields benzoic acid (a white solid).

174 Easy

174 of 255

Understanding +4 | -1

Ethane can be obtained from ethanal in one step by:

View answer and explanation

Correct option: B

Zn-Hg + conc. HCl

Option B (Zn-Hg + conc. HCl) is correct because Clemmensen reduction uses zinc amalgam and concentrated hydrochloric acid to reduce carbonyl groups (C=O) to methylene groups (CH2).

175 Medium

175 of 255

Understanding +4 | -1

Assertion (A): A bright silver mirror is produced during the warming of an aldehyde with freshly prepared ammoniacal silver nitrate solution.

Reason (R): A bright silver mirror is produced due to the formation of silver metal.

View answer and explanation

Correct option: A

Both

\mathrm{A}

and

\mathrm{R}

are correct; and

\mathrm{R}

is the correct explanation of

\mathrm{A}

The correct answer is Both

\mathrm{A}

and

\mathrm{R}

are correct; and

\mathrm{R}

is the correct explanation of

\mathrm{A}

because the formation of a silver mirror is due to the reduction of silver ions to silver metal by the aldehyde.

176 Medium

176 of 255

Analyzing +4 | -1

The most acidic of the following is

View answer and explanation

Correct option: A

\mathrm{ClC}{\mathrm{H}_2}\mathrm{COOH}

Option A (

\mathrm{ClC}{\mathrm{H}_2}\mathrm{COOH}

) is correct because the electron-withdrawing chlorine atom increases the acidity through the -I effect.

177 Medium

177 of 255

Application +4 | -1

Nitration of salicylic acid will give:

View answer and explanation

Correct option: A

2,4,6-trinitophenol

Option A (2,4,6-trinitrophenol) is correct because the -COOH group of salicylic acid is replaced during nitration, leading to the formation of picric acid (2,4,6-trinitrophenol).

178 Medium

178 of 255

Application +4 | -1

The products A and B are

\left(\mathrm{CH}_3\right)_3 \mathrm{C}-\mathrm{CHO} \xrightarrow[\text { (ii) } \mathrm{H}^{+}]{\text {(i) } \mathrm{con.}{\mathrm{NaOH}}} \mathrm{A}+\mathrm{B}

View answer and explanation

Correct option: C

\mathrm{A}=\left(\mathrm{CH}_3\right)_3 \mathrm{C}-\mathrm{CH}_2-\mathrm{OH}, \mathrm{B}=\left(\mathrm{CH}_3\right)_3 \mathrm{C}-\mathrm{COOH}

Option C (A=(CH3)3C-CH2-OH, B=(CH3)3C-COOH) is correct because the reaction is a Cannizzaro reaction, which produces an alcohol and a carboxylic acid.

179 Easy

179 of 255

Remembering +4 | -1

Acetophenone is used in:

View answer and explanation

Correct option: C

Perfumery

Option C (Perfumery) is correct because acetophenone has a pleasant odor and is commonly used as a fragrance component in perfumes.

180 Easy

180 of 255

Understanding +4 | -1

The reaction of acetaldehyde with Tollen’s reagent gives

View answer and explanation

Correct option: D

Acetic acid

Option D (Acetic acid) is correct because acetaldehyde is oxidized to acetic acid when it reacts with Tollen's reagent, which is a mild oxidizing agent.

Revision notes and key takeaways

Review ALDEHYDES & KETONES & CARBOXYLIC ACIDS in your textbook or class notes, then use this set to check your understanding.

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