Question

Which among the following has lowest boiling point?

• A. n - Butyl alcohol
• B. Isobutyl alcohol
• C. sec-Butyl alcohol
• D. tert-Butyl alcohol

Hint:

More branching means a smaller surface area and weaker van der Waals forces.

Answer 1

The Correct Option is D

Step 1: Compare shapes:
n-Butyl: straight chain. Isobutyl: one branch at the end. sec-Butyl: branch in the middle. tert-Butyl: three methyl groups on one carbon.

Step 2: Link to boiling point:
Compact shapes touch fewer neighbouring molecules, so van der Waals attraction is lower. The compact tert-butyl alcohol therefore boils lowest.

Final Answer:
The answer is tert-butyl alcohol, option (D). \[ \boxed{\text{tert-Butyl alcohol}} \]