Which one of the following statement is correct ?

Options

A. From a mixed precipitate of `AgCl` and `AgI` , ammonia solution dissolves only `AgCl` completely.
B. `I^(-)`ions gives red precipitate with `Hg_(2)^(2+)` ions solution
C. On boiling a solution having `Ca^(2+),K` and `HCO_(3)` ions we get white precipitate.
D. `(1)` and `(3)` both

Explanation

To determine which statement is correct among the given options, let's analyze each statement step by step.

### Step 1: Analyze Statement A
**Statement A:** From a mixed precipitate of AgCl and AgI, ammonia solution dissolves only AgCl completely, and AgI is not soluble.

- **Explanation:**
- AgCl (Silver Chloride) is known to dissolve in ammonia due to the formation of a soluble complex, specifically \[ \text{Ag(NH}_3\text{)}_2^+ \text{Cl}^- \].
- AgI (Silver Iodide), on the other hand, does not form a similar soluble complex with ammonia and remains insoluble.

**Conclusion:** Statement A is correct.

### Step 2: Analyze Statement B
**Statement B:** The iodide ions give a red precipitate with the Hg2²⁺ ion.

- **Explanation:**
- The reaction between iodide ions (I⁻) and mercury(I) ions (Hg2²⁺) typically produces a yellow precipitate of mercurous iodide (HgI).
- Therefore, the statement that it gives a red precipitate is incorrect.

**Conclusion:** Statement B is false.

### Step 3: Analyze Statement C
**Statement C:** On boiling a solution having calcium, potassium, and bicarbonate ions, we get a white precipitate.

- **Explanation:**
- When a solution containing bicarbonate ions is boiled, the bicarbonate can decompose to form carbonate ions, but neither calcium nor potassium bicarbonate forms a precipitate upon boiling.
- Calcium carbonate can precipitate under certain conditions, but in the presence of potassium, this does not occur as potassium salts are generally soluble.

**Conclusion:** Statement C is false.

### Final Conclusion
After analyzing all the statements, we find that **Statement A is the only correct statement**.

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