What happens when
(i) n-butyl chloride is treated with alcoholic KOH,
(ii) bromobenzene is treated with Mg in the presence of dry ether,
(iii) chlorobenzene is subjected to hydrolysis,
(iv) ethyl chloride is treated with aqueous KOH,
(v) methyl bromide is treated with sodium in the presence of dry ether,
(vi) methyl chloride is treated with KCN?

Explanation

Let's break down the question step by step:

### (i) n-butyl chloride is treated with alcoholic KOH
1. **Starting Material**: n-butyl chloride (C4H9Cl).
2. **Reaction Type**: This is an elimination reaction (dehydrohalogenation).
3. **Mechanism**:
- The alcoholic KOH dissociates into K⁺ and OH⁻ ions.
- The Cl⁻ ion is eliminated, and a hydrogen atom is removed from an adjacent carbon.
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