Question

Identify the product obtained when isopropyl magnesium chloride in dry ether reacts with dry ice forming a complex, hydrolysed further.

• A. Propanoic acid
• B. Propanal
• C. 2 - Methylpropanoic acid
• D. 2 - Methylpropanol

Hint:

A Grignard reagent adds to CO2 to give a carboxylic acid with one more carbon.

Answer 1

The Correct Option is C

Step 1: Count the carbons:
The Grignard reagent supplies 3 carbons, with the metal on the middle one. Carbon dioxide supplies 1 more. So the acid has 4 carbons in total.

Step 2: Place the COOH:
The new carboxyl group attaches to the carbon that carried magnesium, which is the middle carbon of the isopropyl group. That carbon therefore also keeps two methyl groups: $(\text{CH}_3)_2\text{CH-COOH}$.

Step 3: Name:
Longest chain: 3 carbons (propanoic acid) with a methyl on C2, so 2-methylpropanoic acid.
Propanoic acid has only three carbons, and propanal and 2-methylpropanol are not carboxylation products.

Final Answer:
Option (C). \[ \boxed{\text{2-Methylpropanoic acid (C)}} \]