Consider the following reaction: Identify the product A .

When carboxylic acid reacts with phosphorous pentoxide, acid anhydride is formed as a product. Hence, product for the given reaction is acid anhydride. Acid anhydride is a carboxylic acid derivative with two acyl groups bonded to the same oxygen atom. The mechanism for the reaction can be given as : Note : Acid anhydride is a carboxylic acid derivative formed by dehydration of carboxylic acids.

Why benzoic acid does not undergo Friedel-crafts reaction?

When the carboxyl group is attached to the benzene ring, so it acts as a deactivating and meta-directing group. It decreases the electron density on the benzene ring, therefore they undergo electrophilic substitution reaction. In the Friedel-Craft reaction, AlCl 3 is used which acts as a Lewis acid, so it bonds with the carboxyl group, not with the benzene. Therefore, benzoic acid does not undergo a Friedel-Craft reaction.

E M B I B E

All In One ISC Chemistry Class 12>Chapter 12 - Aldehydes, Ketones and Carboxylic Acids>Chapter Practice>Q 11

HARD

12th ICSE

IMPORTANT

Earn 100

Carry out the following conversion: Benzene to benzoic acid.

Important Questions on Aldehydes, Ketones and Carboxylic Acids

MEDIUM

12th ICSE

IMPORTANT

All In One ISC Chemistry Class 12>Chapter 12 - Aldehydes, Ketones and Carboxylic Acids>Chapter Practice>Q 12

{pK}_{a}

of chloroacetic acid is lower than

{pK}_{a}

of acetic acid. Why?

MEDIUM

12th ICSE

IMPORTANT

All In One ISC Chemistry Class 12>Chapter 12 - Aldehydes, Ketones and Carboxylic Acids>Chapter Practice>Q 13

Why is

C - O

bond shorter in

RCOOH

than in

RCHO

?

HARD

12th ICSE

IMPORTANT

All In One ISC Chemistry Class 12>Chapter 12 - Aldehydes, Ketones and Carboxylic Acids>Chapter Practice>Q 14

Complete the following reaction :

Question Image

HARD

12th ICSE

IMPORTANT

All In One ISC Chemistry Class 12>Chapter 12 - Aldehydes, Ketones and Carboxylic Acids>Chapter Practice>Q 15

Consider the following reaction:

Question Image

Identify the product $(A)$ .

HARD

12th ICSE

IMPORTANT

All In One ISC Chemistry Class 12>Chapter 12 - Aldehydes, Ketones and Carboxylic Acids>Chapter Practice>Q 16

Give one example of the following name reaction: Benzoin condensation.

HARD

12th ICSE

IMPORTANT

All In One ISC Chemistry Class 12>Chapter 12 - Aldehydes, Ketones and Carboxylic Acids>Chapter Practice>Q 17

Correct the following statement by changing the underlined part of the sentence (Do not change the whole sentence).

Acetone gives a white precipitate on treatment with sodium chloride.

HARD

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IMPORTANT

All In One ISC Chemistry Class 12>Chapter 12 - Aldehydes, Ketones and Carboxylic Acids>Chapter Practice>Q 17

Correct the following statements by changing the underlined part of the sentence
(Do not change the whole sentence). Acetaldehyde undergoes Cannizzaro's reaction on treatment with dilute alkali.

HARD

12th ICSE

IMPORTANT

All In One ISC Chemistry Class 12>Chapter 12 - Aldehydes, Ketones and Carboxylic Acids>Chapter Practice>Q 18

Draw the structures of vanillin, cinnamaldehyde and salicylaldehyde.