Assertion: A solution of AgCl in `NH_(4)OH` gives a white precipitate when acidified with `HNO_(3)`.
Reason: `[Ag(NH_(3))_(2)]^(+)` decomposes in the presence of `HNO_(3)`.

Options

A. If assertion is true but the reason is false
B. If assertion is false but reason is true
C. If both assertion and reason are true and reason is the correct explanation of assertion
D. If oth assertion and reason are true but reason is not the correct explanation of assertion

Answer

To solve the assertion and reason question, we will break down the information provided in the assertion and the reason step by step.

### Step 1: Understanding the Assertion
The assertion states that a solution of AgCl in NH4OH gives a white precipitate when acidified with HNO3.

1. **Formation of the Complex**: When silver chloride (AgCl) is mixed with ammonium hydroxide (NH4OH), it forms a complex ion, [Ag(NH3)2]+ (known as diamine silver ion) and Cl- remains in solution.

\[ \text{AgCl (s)} + 2 \text{NH}_4\text{OH (aq)} \rightarrow [\text{Ag(NH}_3)_2]^+ + \text{Cl}^- + \text{H}_2\text{O} \]

2. **Acidification**: When this solution is acidified with nitric acid (HNO3), the diamine silver complex decomposes to form silver chloride again and ammonium nitrate.

\[ [\text{Ag(NH}_3)_2]^+ + \text{HNO}_3 \rightarrow \text{AgCl (s)} + \text{NH}_4\text{NO}_3 \]

3. **Precipitate Formation**: The silver chloride (AgCl) formed is a white precipitate.

### Conclusion for Step 1:
The assertion is true because acidifying the solution leads to the formation of a white precipitate of AgCl.

### Step 2: Understanding the Reason
The reason states that [Ag(NH3)2]+ decomposes in the presence of HNO3.

1. **Decomposition Reaction**: The reason correctly describes the reaction that occurs when the diamine silver complex is treated with nitric acid. The complex does indeed decompose, leading to the formation of AgCl and NH4NO3.

### Conclusion for Step 2:
The reason is also true because it accurately describes the chemical behavior of the diamine silver complex in the presence of nitric acid.

### Final Conclusion:
Both the assertion and the reason are true, and the reason is the correct explanation of the assertion. Therefore, the correct answer is option C: "Both assertion and reason are true, and reason is the correct explanation of assertion."

---