n-Propyl alcohol and isopropyl alcohol can be chemically distinguished by which reagent `:`

Options

A. `PCl_5`
B. Reduction
C. Oxidation with Potassium dichromate
D. Oznolysis

Answer

To distinguish between n-propyl alcohol and isopropyl alcohol, we can use potassium dichromate (K2Cr2O7) as a reagent. Here’s a step-by-step explanation of how this works:

### Step 1: Identify the Structures
- **n-Propyl alcohol (1-propanol)** has the structure: CH3-CH2-CH2-OH (a primary alcohol).
- **Isopropyl alcohol (2-propanol)** has the structure: CH3-CHOH-CH3 (a secondary alcohol).

### Step 2: Understand the Classification
- n-Propyl alcohol is classified as a **primary alcohol** because the carbon atom bonded to the hydroxyl (-OH) group is attached to only one other carbon atom.
- Isopropyl alcohol is classified as a **secondary alcohol** because the carbon atom bonded to the hydroxyl (-OH) group is attached to two other carbon atoms.

### Step 3: Reaction with Potassium Dichromate
- Potassium dichromate (K2Cr2O7) is a strong oxidizing agent.
- When n-propyl alcohol is treated with K2Cr2O7, it undergoes oxidation to form propanoic acid (CH3-CH2-COOH). The oxidation process involves an intermediate aldehyde (propanal) before forming the carboxylic acid.
- The color change of potassium dichromate from orange to green indicates the oxidation of the primary alcohol to a carboxylic acid.

### Step 4: Reaction of Isopropyl Alcohol
- When isopropyl alcohol is treated with K2Cr2O7, it gets oxidized to acetone (propanone, CH3-CO-CH3). The oxidation of secondary alcohols generally leads to ketones.
- The color change of potassium dichromate also occurs, but it happens more rapidly than with primary alcohols.

### Step 5: Observing the Results
- By observing the reaction and the products formed, we can distinguish between n-propyl alcohol and isopropyl alcohol:
- **n-Propyl alcohol**: Forms propanoic acid and shows a gradual color change from orange to green.
- **Isopropyl alcohol**: Forms acetone and shows a more rapid color change.

### Conclusion
Thus, the reagent that can chemically distinguish between n-propyl alcohol and isopropyl alcohol is **potassium dichromate (K2Cr2O7)**.

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