Which one of the following statement is correct ?

Options

A. From a mixed precipitate of AgCl of Agl, ammonia solution dissolves only AgCl completely
B. `I^-` ions gives red precipitate with `Hg_2^(2+)` ion solution
C. On boiling a solution having `Ca^(2+), K^(+) and HCO_3` ions we get white precipitate
D. (A) and (C ) both

Explanation

To determine which statement is correct, we will analyze each statement one by one.

1. **Statement 1**: "From a mixed precipitate of AgCl and AgI, ammonia solution dissolves only AgCl completely."
- When AgCl is treated with ammonia, it forms a soluble complex, [Ag(NH3)2]Cl. This means AgCl can dissolve in ammonia.
- On the other hand, AgI does not form a similar complex with ammonia and remains insoluble.
- Therefore, this statement is **correct**.

2. **Statement 2**: "I⁻ ions give red precipitate with Hg2²⁺ ion solution."
- When I⁻ ions react with Hg2²⁺ ions, they do not form a red precipitate. Instead, they form HgI2, which is a yellow solution. Furthermore, excess I⁻ can lead to the formation of the complex ion [HgI4]²⁻.
- Therefore, this statement is **incorrect**.

3. **Statement 3**: "On boiling a solution having Ca²⁺, K⁺, and HCO3⁻ ions, we get a white precipitate."
- When boiling a solution containing Ca²⁺ and HCO3⁻, calcium bicarbonate decomposes to form calcium carbonate (CaCO3), which is a white precipitate. However, K⁺ does not affect this reaction as it does not form a precipitate with bicarbonate.
- Therefore, this statement is also **incorrect**.

After analyzing all the statements, we conclude that the only correct statement is **Statement 1**.

### Summary of Steps:
1. Analyze Statement 1: AgCl dissolves in ammonia, AgI does not.
2. Analyze Statement 2: I⁻ does not give a red precipitate with Hg2²⁺.
3. Analyze Statement 3: Boiling Ca²⁺ and HCO3⁻ does lead to a white precipitate (CaCO3).
4. Determine the correct statement: Only Statement 1 is correct.