Primary alkyl halide `C_(4)H_(9)Br` (a) reacted with alcoholic KOH to give compound (b). Compound (b) is reacted with HBr to give (c) which is an isomer of (a). When (a) is reacted with sodium metal it gives compound (d), `C_(8)H_(18)` which is different from the compound formed when n-butyl bromide is reacted with sodium. Give the structural formula of (a) and write the equations for all the reactions.

Explanation

To solve the problem step by step, we will identify the compounds and write the corresponding reactions.

### Step 1: Identify Compound (a)
Given the molecular formula \( C_4H_9Br \), we need to determine the structure of the primary alkyl halide. The only primary alkyl halide that fits this formula is **isobutyl bromide**.

**Structure of (a):**
- Isobutyl bromide can be represented as:

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