Which of the following gives positive Tollens test?

(A) Phenylethanal
(B) Acetophenone
(C) Formic acid
(D) Benzene carbaldehyde

Choose the correct answer from the options given below:

(A), (C) and (D) only

The correct answer is Option (4) → (A), (C) and (D) only
Tollens’ reagent  gives a silver mirror test with aldehydes and with compounds that can be easily oxidized to carbon dioxide, such as formic acid. Ketones generally do not give Tollens’ test.

• (A) Phenylethanal – It is an aldehyde, so it reduces Tollens’ reagent and gives a positive test.

• (B) Acetophenone – It is a ketone, and ketones do not reduce Tollens’ reagent, so the test is negative.

• (C) Formic acid – It behaves like an aldehyde and is oxidized to CO₂, therefore it gives a positive Tollens’ test.

• (D) Benzene carbaldehyde (benzaldehyde) – It is an aromatic aldehyde, so it gives a positive Tollens’ test.

Therefore, compounds (A), (C), and (D) give a positive Tollens test.