CBSE Class 12 Chemistry MCQs for Aldehydes, Ketones and Carboxylic Acids

The chapter on Aldehydes, Ketones and Carboxylic Acids is one of the most important topics in the CBSE Class 12 Chemistry Syllabus. Students often find this chapter challenging because it include many reactions, mechanism and properties. To make preparation more easy, solving CBSE Class 12 Chemistry MCQs for Aldehydes, Ketones and Carboxylic Acids is very useful. Practicing multiple choice questions help learners to test concept understanding and improve problem solving speed.

These MCQs on Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids MCQs are design according to NCERT Solutions and follow the pattern of board exams. They are also connected with NCERT Solutions for Class 12 Chemistry, so that students can revise the concepts quickly. By solving aldehydes ketones and carboxylic acids mcq regularly, students can identify weak areas and focus more on revision.

This set of questions cover all key subtopics like preparation, physical properties, chemical properties and important named reactions. With repeated practice of aldehyde ketone and carboxylic acids mcq or mcq on aldehydes ketones and carboxylic acids, students gain confidence for cbse class 12 board exam.

Class 12 Chemistry MCQs Aldehydes, Ketones and Carboxylic Acids

Here is a set of CBSE Class 12 Chemistry MCQs with answers and explanations for the chapter Aldehydes, Ketones and Carboxylic Acids.

Ques: The functional group of aldehyde is:

a) –COOH

b) –CHO

c) –CO–

d) –OH

Answer: b) –CHO

Explanation: Aldehydes contain the –CHO group where carbon is attached to hydrogen and double bonded to oxygen.

Ques: The common name of methanal is:

a) Formaldehyde

b) Acetaldehyde

c) Acetone

d) Formic acid

Answer: a) Formaldehyde

Explanation: Methanal (HCHO) is known as formaldehyde, widely used as a preservative.

Ques: The IUPAC name of CH3–CO–CH3 is:

a) Acetaldehyde

b) Propanone

c) Butanone

d) Acetone

Answer: b) Propanone

Explanation: CH3–CO–CH3 is a ketone with three carbons. IUPAC name is propanone.

Ques: Tollen’s reagent is used to test for:

a) Ketones

b) Aldehydes

c) Carboxylic acids

d) Alcohols

Answer: b) Aldehydes

Explanation: Aldehydes reduce Tollen’s reagent (ammoniacal AgNO3) to form silver mirror.

Ques: Which of the following gives iodoform test?

a) Acetone

b) Formaldehyde

c) Benzaldehyde

d) Formic acid

Answer: a) Acetone

Explanation: Compounds with –COCH3 group give iodoform test. Acetone has this group.

Ques: The reduction of aldehydes to primary alcohols is carried out by:

a) LiAlH4

b) H2/Pd

c) NaBH4

d) All of these

Answer: d) All of these

Explanation: Strong and mild reducing agents both reduce aldehydes to primary alcohols.

Ques: The product of oxidation of ketones is:

a) Alcohols

b) Aldehydes

c) Acids

d) None under mild conditions

Answer: d) None under mild conditions

Explanation: Ketones are resistant to mild oxidizing agents. They oxidize with strong agents to give acids.

Ques: The carboxylic group is represented as:

a) –COH

b) –COOH

c) –CO–

d) –OH

Answer: b) –COOH

Explanation: Carboxylic acids contain –COOH group.

Ques: The acidity of carboxylic acid is due to:

a) C=O group

b) –OH group

c) Resonance stabilization of carboxylate ion

d) None

Answer: c) Resonance stabilization of carboxylate ion

Explanation: The carboxylate ion is stabilized by resonance, increasing acidity.

Ques: Which of the following has the highest boiling point?

a) Aldehydes

b) Ketones

c) Carboxylic acids

d) Alcohols

Answer: c) Carboxylic acids

Explanation: Carboxylic acids form strong hydrogen bonds (dimeric), leading to high boiling point.

Ques: Aldol condensation involves:

a) Acidic medium

b) Basic medium

c) Neutral medium

d) Oxidizing medium

Answer: b) Basic medium

Explanation: Aldol condensation occurs in basic medium due to enolate ion formation.

Ques: Which acid is used in vinegar?

a) Formic acid

b) Acetic acid

c) Oxalic acid

d) Propanoic acid

Answer: b) Acetic acid

Explanation: Vinegar contains 5–8% acetic acid.

Ques: Which of the following is most reactive towards nucleophilic addition?

a) Formaldehyde

b) Acetaldehyde

c) Acetone

d) Benzaldehyde

Answer: a) Formaldehyde

Explanation: Less steric hindrance and strong electrophilicity make formaldehyde most reactive.

Ques: Which compound does not give Fehling’s test?

a) Acetaldehyde

b) Formaldehyde

c) Benzaldehyde

d) Ethanol

Answer: c) Benzaldehyde

Explanation: Aromatic aldehydes generally do not give Fehling’s test.

Ques: Esterification of carboxylic acid is carried out in the presence of:

a) Base

b) H2SO4

c) HCl

d) NaOH

Answer: b) H2SO4

Explanation: Conc. H2SO4 acts as catalyst and dehydrating agent in esterification.

Ques: Formalin is:

a) 40% formaldehyde in water

b) 10% formic acid in water

c) Pure aldehyde

d) None

Answer: a) 40% formaldehyde in water

Explanation: Formalin is aqueous solution of formaldehyde.

Ques: Benzaldehyde on oxidation gives:

a) Benzoic acid

b) Benzyl alcohol

c) Acetophenone

d) Phenol

Answer: a) Benzoic acid

Explanation: Mild oxidation converts benzaldehyde to benzoic acid.

Ques: Acetone reacts with hydrazine to form:

a) Oxime

b) Hydrazone

c) Semicarbazone

d) Phenylhydrazone

Answer: b) Hydrazone

Explanation: Ketones react with hydrazine to form hydrazones.

Ques: The reaction between acid chloride and alcohol gives:

a) Amide

b) Anhydride

c) Ester

d) Aldehyde

Answer: c) Ester

Explanation: Alcohol reacts with acid chloride in esterification reaction.

Ques: The acidity of formic acid is due to:

a) Formyl group

b) Resonance

c) –OH group

d) Carboxyl group

Answer: d) Carboxyl group

Explanation: Formic acid has –COOH group responsible for acidity.

Ques: Which compound gives positive iodoform test?

a) Propanone

b) Propanal

c) Benzaldehyde

d) Methanol

Answer: a) Propanone

Explanation: Compounds with –COCH3 group (like acetone) give positive test.

Ques: Which of the following is not a carbonyl compound?

a) Formaldehyde

b) Acetone

c) Methanoic acid

d) Benzaldehyde

Answer: c) Methanoic acid

Explanation: Carboxylic acids are not classified as carbonyl compounds for this context.

Ques: Which is the strongest acid?

a) Formic acid

b) Acetic acid

c) Benzoic acid

d) Propanoic acid

Answer: a) Formic acid

Explanation: Absence of electron-donating alkyl groups makes formic acid strongest.

Ques: Ketones on reduction give:

a) Primary alcohols

b) Secondary alcohols

c) Aldehydes

d) Carboxylic acids

Answer: b) Secondary alcohols

Explanation: Reduction of ketones leads to secondary alcohols.

Ques: Acetaldehyde reacts with HCN to form:

a) Hydroxynitrile

b) Alcohol

c) Aldol

d) Carboxylic acid

Answer: a) Hydroxynitrile

Explanation: Nucleophilic addition of HCN to aldehydes gives cyanohydrin.

Ques: Which acid is dicarboxylic?

a) Acetic acid

b) Oxalic acid

c) Formic acid

d) Benzoic acid

Answer: b) Oxalic acid

Explanation: Oxalic acid has two –COOH groups.

Ques: Cannizzaro reaction is shown by:

a) Formaldehyde

b) Acetone

c) Propanal

d) Acetaldehyde

Answer: a) Formaldehyde

Explanation: Aldehydes without α-hydrogen (like HCHO) undergo Cannizzaro reaction.

Ques: Acetone is commonly called:

a) Nail polish remover

b) Vinegar

c) Spirit

d) Ether

Answer: a) Nail polish remover

Explanation: Acetone is used as solvent in nail polish removers.

Ques: Which is a derivative of acetic acid?

a) Acetyl chloride

b) Acetic anhydride

c) Ethyl acetate

d) All of these

Answer: d) All of these

Explanation: All are derivatives of acetic acid.

Ques: Which reaction converts aldehydes into alcohols?

a) Oxidation

b) Reduction

c) Substitution

d) Hydrolysis

Answer: b) Reduction

Explanation: Aldehydes reduce to primary alcohols.