Give one good test to distinguish between the following pair compounds : oxalic acid and benzoic acid.

Explanation

To distinguish between oxalic acid and benzoic acid, we can use the potassium permanganate test. Here’s a step-by-step solution:

### Step 1: Understand the Compounds
- **Oxalic Acid**: The chemical formula is H₂C₂O₄. It has two carboxylic acid (-COOH) groups.
- **Benzoic Acid**: The chemical formula is C₆H₅COOH. It has one carboxylic acid group attached to a benzene ring.

### Step 2: Prepare Potassium Permanganate Solution
- Take a dilute solution of potassium permanganate (KMnO₄). This solution is purple in color.
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