Which of the following can be oxidised to alcohol by `KMnO_(4)` :-

Options

A. n-pentane
B. Iso pentane
C. Neo pentane
D. propane

Answer

To determine which of the given compounds can be oxidized to alcohol by KMnO4, we need to analyze the structures of the compounds and identify the presence of tertiary hydrogens. Here’s a step-by-step solution:

### Step 1: Understand the Role of KMnO4
KMnO4 is a strong oxidizing agent that can oxidize certain hydrocarbons to alcohols, particularly those that contain tertiary hydrogens. Tertiary hydrogens are found on tertiary carbons, which are carbons bonded to three other carbons.

**Hint:** Remember that KMnO4 can oxidize only those hydrocarbons that have tertiary hydrogens.

### Step 2: Analyze Each Compound
1. **n-Pentane (CH3-CH2-CH2-CH2-CH3)**:
- Structure: A straight-chain alkane with no tertiary carbon.
- Analysis: Contains only primary and secondary carbons. No tertiary hydrogen is present.
- Conclusion: Cannot be oxidized to alcohol.

**Hint:** Look for the presence of tertiary carbons in the structure.

2. **Isopentane (CH3-CH(CH3)-CH2-CH3)**:
- Structure: A branched alkane with one tertiary carbon.
- Analysis: The central carbon (C2) is bonded to three other carbons (C1, C3, and C4), indicating it is a tertiary carbon.
- Conclusion: Can be oxidized to alcohol.

**Hint:** Identify the carbon types (primary, secondary, tertiary) in the structure.

3. **Neopentane (C5H12)**:
- Structure: (CH3)4C, a carbon bonded to four other carbons.
- Analysis: The central carbon is a quaternary carbon (bonded to four other carbons), and there are no tertiary hydrogens.
- Conclusion: Cannot be oxidized to alcohol.

**Hint:** Quaternary carbons do not have hydrogens that can be oxidized.

4. **Propane (CH3-CH2-CH3)**:
- Structure: A straight-chain alkane with no tertiary carbon.
- Analysis: Contains only primary and secondary carbons. No tertiary hydrogen is present.
- Conclusion: Cannot be oxidized to alcohol.

**Hint:** Similar to n-pentane, check for tertiary hydrogens.

### Step 3: Final Conclusion
Based on the analysis, the only compound that can be oxidized to alcohol by KMnO4 is **isopentane**.

**Final Answer:** Isopentane can be oxidized to alcohol by KMnO4.