Question

Which of the following alcohols needs acidic KMnO\(_4\) to convert it into aldehyde or ketone?

• A. Ethanol
• B. Propan -1-ol
• C. Propan -2-ol
• D. 2-Methyl propan -2-ol

Hint:

KMnO\(_4\) is effective for oxidizing primary and secondary alcohols, but tertiary alcohols are usually resistant to oxidation.

Answer 1

The Correct Option is C

Step 1: Understanding the use of KMnO\(_4\).
KMnO\(_4\) is a strong oxidizing agent that can oxidize alcohols to aldehydes or ketones. Secondary alcohols like propan-2-ol are oxidized to ketones by KMnO\(_4\), while primary alcohols can be converted into aldehydes.

Step 2: Analyzing the options.
(A) Ethanol: Ethanol is a primary alcohol and needs a stronger oxidizer to convert it to an aldehyde.
(B) Propan-1-ol: Propan-1-ol is a primary alcohol, which requires KMnO\(_4\) for oxidation to an aldehyde, not a ketone.
(C) Propan-2-ol: This is a secondary alcohol that reacts with KMnO\(_4\) to form acetone (a ketone).
(D) 2-Methyl propan-2-ol: This is a tertiary alcohol, which is generally resistant to oxidation by KMnO\(_4\).

Step 3: Conclusion.
The correct answer is (C) Propan-2-ol, which can be oxidized by KMnO\(_4\) to a ketone.