Question

A compound (A) C7H6O reacts with Tollen's
reagent and forms a silver mirror. On
oxidation, (A) gives (B) C7H6O2which gives
effervescences with NaHCO3 Write the
structures and names of (A) and (B).

Answer 1

Answer:

A: Benzaldehyde - C7H6O

B: Benzoic acid - C7H6O2

Explanation:

• Benzaldehyde being a carbonyl compound gives positive response to Tollen's reagent.
• Benzaldehyde on oxidation gives Benzoic acid- C7H6O2

EQUATION:

Benzaldehyde + Tollen's reagent -->  Benzoic acid + 2Ag ( Silver Mirror)

• Benzoic acid contain a Carboxyl group- COOH which releases CO2 gas on reaction with NaHCO3.

• This CO released is responsible for the effervescence.

EQUATION:

C6H5COOH + NaHCO3 ---> NaC6H5COO + H2O(l) + CO2(g)

Hope this helps :)