Which of the following compounds will give silver mirror with ammoniacal silver nitrate? A. Formic acid B. Formaldehyde C. Benzaldehyde D. Acetone Choose the correct answer from the options given below :

Aldehydes Ketones and Carboxylic Acids PYQ — JEE Main 2024 · 9 Apr · Shift 2 · Q7 with Solution

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Correct answer: C

Identify the reagent

Ammoniacal silver nitrate is Tollens' reagent, written as $[Ag(NH_3)_2]^+.$ Compounds that reduce Tollens' reagent give a silver mirror.
Compounds that respond to Tollens' reagent

Tollens' reagent is reduced by:
- Aldehydes
- Formic acid (and formates), because it is easily oxidized to $CO_2$
Check each compound

A. Formic acid $(HCOOH)$
- Formic acid is oxidized to $CO_2$ .
- Hence it reduces Tollens' reagent.
- So A gives silver mirror.
B. Formaldehyde $(HCHO)$
- Formaldehyde is an aldehyde.
- All aldehydes generally give Tollens' test.
- So B gives silver mirror.
C. Benzaldehyde $(C_6H_5CHO)$
- Benzaldehyde is also an aldehyde.
- Therefore it gives Tollens' test.
- So C gives silver mirror.
D. Acetone $(CH_3COCH_3)$
- Acetone is a ketone.
- Ordinary ketones do not reduce Tollens' reagent.
- So D does not give silver mirror.
Final selection

Compounds giving silver mirror are: $A, B, C$

Therefore the correct option is: $\boxed{\text{C: A, B and C only}}$
Comparison with stored answer

Stored correct answer = C

My derived answer = C

Hence, they agree.

View written solutionFree

Correct answer: C

Identify the reagent

Ammoniacal silver nitrate is Tollens' reagent, written as $[Ag(NH_3)_2]^+.$ Compounds that reduce Tollens' reagent give a silver mirror.
Compounds that respond to Tollens' reagent

Tollens' reagent is reduced by:
- Aldehydes
- Formic acid (and formates), because it is easily oxidized to $CO_2$
Check each compound

A. Formic acid $(HCOOH)$
- Formic acid is oxidized to $CO_2$ .
- Hence it reduces Tollens' reagent.
- So A gives silver mirror.
B. Formaldehyde $(HCHO)$
- Formaldehyde is an aldehyde.
- All aldehydes generally give Tollens' test.
- So B gives silver mirror.
C. Benzaldehyde $(C_6H_5CHO)$
- Benzaldehyde is also an aldehyde.
- Therefore it gives Tollens' test.
- So C gives silver mirror.
D. Acetone $(CH_3COCH_3)$
- Acetone is a ketone.
- Ordinary ketones do not reduce Tollens' reagent.
- So D does not give silver mirror.
Final selection

Compounds giving silver mirror are: $A, B, C$

Therefore the correct option is: $\boxed{\text{C: A, B and C only}}$
Comparison with stored answer

Stored correct answer = C

My derived answer = C

Hence, they agree.