Which of the following alcohols does not give an aldehyde on oxidation ?

Options

A. Benzyl alcohol
B. Sec. butyl alcohol
C. Allyl alcohol
D. Crotyl alcohol

Answer

To determine which alcohol does not give an aldehyde upon oxidation, we need to analyze the oxidation behavior of each option provided. Here’s a step-by-step breakdown of the solution:

### Step 1: Identify the Types of Alcohols
We need to recall the types of alcohols:
- **Primary Alcohols**: Oxidation leads to aldehydes.
- **Secondary Alcohols**: Oxidation leads to ketones.
- **Tertiary Alcohols**: Generally do not oxidize to form aldehydes or ketones.

### Step 2: Analyze Each Option
Let’s analyze each of the provided options to see what they yield upon oxidation.

1. **Benzyl Alcohol (C6H5CH2OH)**:
- Benzyl alcohol is a primary alcohol. Upon oxidation, it will yield benzaldehyde (an aldehyde).
- **Conclusion**: Benzyl alcohol gives an aldehyde.

2. **Allyl Alcohol (CH2=CH-CH2OH)**:
- Allyl alcohol is also a primary alcohol. Upon oxidation, it will yield acrolein (an aldehyde).
- **Conclusion**: Allyl alcohol gives an aldehyde.

3. **Crotyl Alcohol (CH3-CH=CH-CH2OH)**:
- Crotyl alcohol is a primary alcohol as well. Upon oxidation, it will yield crotonaldehyde (an aldehyde).
- **Conclusion**: Crotyl alcohol gives an aldehyde.

4. **Isopropyl Alcohol (2-Propanol, (CH3)2CHOH)**:
- Isopropyl alcohol is a secondary alcohol. Upon oxidation, it will yield acetone (a ketone).
- **Conclusion**: Isopropyl alcohol does not give an aldehyde.

### Step 3: Final Answer
Based on the analysis, the alcohol that does not give an aldehyde upon oxidation is **Isopropyl Alcohol (2-Propanol)**.

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