A certain compound (A) is used in the laboratory for analysis, its aqueous solution gives the following reactions:
a. On addition to copper sulphate, a brown precipitate is obtained which turns white on addition of excess of the `Na_(2)S_(2)O_(3)` solution.
b. On addition to the `Ag^(o+)` ion solution, a yellow curdy precipitate is obtained which is insoluble in ammonium hydroxide. Identify (A) and give equations for the reactions at steps (a) and (b).

Explanation

To identify the compound (A) and provide the equations for the reactions described, we will analyze the given information step by step.

### Step 1: Identify Compound (A)
The problem states that when a certain compound (A) is added to copper sulfate, a brown precipitate is formed. The brown precipitate turns white upon the addition of excess sodium thiosulfate (Na₂S₂O₃).

**Analysis:**
- The formation of a brown precipitate suggests that the compound (A) likely contains iodide ions (I⁻), as the brown precipitate formed with copper sulfate is cuprous iodide (CuI).
- The reaction of iodine with sodium thiosulfate is known to produce sodium tetrathionate (Na₂S₄O₆) and sodium iodide (NaI), which explains the color change.
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