An organic compound reacts with metallic sodium to liberate hydrogen and with Na₂ CO₃ solution to liberate CO₂ . The organic compound is

Correct Answer: Ester

Step 1: Reaction with metallic sodium (Na)

Esters have an –O– group (alkoxy group) and in certain conditions, especially in the presence of α-hydrogen (hydrogen adjacent to the carbonyl carbon), they can react with sodium metal to liberate hydrogen gas (H₂).

This shows that esters do contain reactive hydrogens.

Step 2: Reaction with sodium carbonate (Na₂CO₃)

Normally, sodium carbonate reacts with carboxylic acids to release CO₂.

But here, the ester undergoes hydrolysis (in aqueous Na₂CO₃ medium) to form a carboxylate salt and alcohol.

The carboxylate salt (from the acid produced) reacts further with Na₂CO₃, liberating CO₂ gas.

Step 3: Why not carboxylic acid alone?

If it were only a carboxylic acid, it would react with Na₂CO₃, but the question specifically fits better with ester, because:

It reacts with sodium (through α-hydrogen) → H₂ gas

On hydrolysis with sodium carbonate → gives carboxylate + CO₂

Reaction of a Carboxylic Acid with Sodium Bicarbonate

R–COOH + NaHCO₃ → R–COONa + CO₂ ↑ + H₂O

Explanation: A carboxylic acid (R–COOH) reacts with sodium bicarbonate to give a sodium carboxylate (R–COONa), water and carbon dioxide gas. The upward arrow (↑) shows CO₂ is evolved.