Identify A and B in the following reaction
(i). `C_(2)H_(5)Broverset(alc.KOH)to[A]overset(Br_(2))to[B]`
(ii). `CH_(3)-CH=CH_(2)overset(HBr)to[A]overset(alc.KOH)to[B]`.

Explanation

To solve the given reactions step by step, we will identify the compounds A and B in both parts of the reaction.

### Part (i):
1. **Identify the Reactant**: The reactant is Bromoethane (C₂H₅Br).
2. **Reaction with Alcoholic KOH**: When Bromoethane reacts with alcoholic KOH, an elimination reaction occurs. In this reaction, HBr is eliminated (dehydrohalogenation), resulting in the formation of an alkene.
3. **Formation of Product A**: The elimination of HBr from Bromoethane leads to the formation of Ethene (C₂H₄). Therefore, A = C₂H₄ (Ethene).
4. **Reaction with Br₂**: Ethene (A) then reacts with bromine (Br₂). This is an addition reaction where bromine adds across the double bond.
5. **Formation of Product B**: The addition of Br₂ to Ethene results in the formation of 1,2-Dibromoethane (C₂H₄Br₂). Therefore, B = C₂H₄Br₂ (1,2-Dibromoethane).
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