Identify A,B,C, ……. `C_(6)H_(5)Clunderset(2.B)overset(1.A)toC_(6)H_(5)COOH`

Explanation

To solve the problem of identifying compounds A and B in the reaction sequence from C₆H₅Cl to C₆H₅COOH, we can break it down into two steps:

### Step 1: Identify Compound A
1. **Starting Compound**: We start with C₆H₅Cl, which is chlorobenzene.
2. **Reaction with Copper Cyanide**: The first step involves the reaction of chlorobenzene (C₆H₅Cl) with copper cyanide (CuCN). This reaction is known as the Gattermann reaction.
3. **Product Formation**: In this reaction, the chlorine atom (Cl) in chlorobenzene is replaced by a cyanide group (CN), resulting in the formation of benzonitrile (C₆H₅CN).

**So, Compound A is Copper Cyanide (CuCN)**.
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