Identify A, B and C in the following reactions.
`C_6H_5NH_2 overset(NaNO_2, HCl)to A underset("pyridine")overset(CuCN)toB overset(Sn//HCl)toC`

Explanation

To identify compounds A, B, and C in the given reactions, let's break down the steps systematically.

### Step 1: Identify Compound A
- The starting compound is **aniline** (C₆H₅NH₂).
- When aniline reacts with **NaNO₂ (sodium nitrite)** in the presence of **HCl**, it forms **benzene diazonium chloride** (C₆H₅N₂Cl). This is a diazonium salt where the amino group (NH₂) is converted into a diazo group (N₂⁺).

**Compound A**: C₆H₅N₂Cl (Benzene diazonium chloride)

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