A scalet compound A is treated with concenbtrated `HNO_(3)`to gave a chocolate brown precipitate B. The precipitate is filtered and the filtrate is neurralised with NaOH Addition of KI to the resulting solution gives a yellow precipitate C the brown precipitate B on warming with concentrated `HNO_(3) `in the presence of `Mn(NO_(3))_(2)` produces a pink coloured solution due to the formation of D identify A, B,C, and D write the reaction sequence.

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 steps systematically.

### Step 1: Identify Compound A
The problem states that a scarlet compound A is treated with concentrated HNO3. The only common scarlet compound that fits this description is lead(II) phosphate, which has the formula **Pb3(PO4)2**.

**Answer:** Compound A is **Pb3(PO4)2**.

### Step 2: Reaction of A with Concentrated HNO3
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