A violet compound of manganese (A) decomposes on heating to liberate oxygen and compounds (B) and (C ) of manganese are formed. Compound (C ) reacts with KOH in the presence of potassium nitrate to give compound (B). On heating compound (C ) with conc. `H_(2)SO_(4)` and NaCl, chlorine gas is liberate and a compound (D) of manganese alongwith other products is formed. Identify compounds A to D and also explain the reaction involved.

Explanation

To solve the problem, we need to identify the compounds A, B, C, and D based on the reactions described in the question. Let's break down the information step by step.

### Step 1: Identify Compound A
The question states that a violet compound of manganese (A) decomposes on heating to liberate oxygen and forms compounds B and C. The violet compound of manganese is known to be **Potassium Permanganate (KMnO4)**.

**Reaction:**
\[ 2 KMnO_4 \rightarrow K_2MnO_4 + MnO_2 + O_2 \]

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