Give a chemical test to distinguise between but `-1-`ene and but `-2-`ene.

Explanation

To distinguish between but-1-ene and but-2-ene, we can perform a chemical test using acidic potassium permanganate (KMnO4) as an oxidizing agent. Here is a step-by-step solution:

### Step 1: Understand the Structures
- **But-1-ene** has the structure: CH2=CH-CH2-CH3
- **But-2-ene** has the structure: CH3-CH=CH-CH3

### Step 2: Perform Oxidation with Acidic KMnO4
- Add a few drops of acidic KMnO4 to separate test tubes containing but-1-ene and but-2-ene.
...