Question

The acid formed when propyl magnesium bromide is treated with CO_2 followed by acid hydrolysis is:

• A. C_3H_7COOH
• B. C_2H_5COOH
• C. CH_3COOH
• D. C_3H_7OH

Hint:

Grignard reagents react with CO_2 to form carboxylates, which can be hydrolyzed to yield carboxylic acids.

Answer 1

The Correct Option is B

Step 1: Reaction Mechanism

Propyl magnesium bromide, a Grignard reagent, reacts with carbon dioxide (CO₂). This reaction first forms a carboxylate ion, which is then hydrolysed to give a carboxylic acid. The reaction sequence is:

RMgBr + CO₂ → RCO⁻ + MgBr⁺

On hydrolysis:

RCO⁻ + H₂O → RCOOH

Step 2: Identification of the Product

Since the Grignard reagent is propyl magnesium bromide (C₃H₇MgBr), the resulting carboxylic acid contains one additional carbon atom.

Thus, the final product is propionic acid (C₃H₇COOH), which corresponds to option (A).