Assertion: AgI does not dissolve in `NH_(3)`.
Reason: Due to ionic character of AgI.

Options

A. If both (A) and (R) are true and (R) is the correct explanation of (A)
B. if both (A) and (R) are true but (R) is not correct explanation of (A)
C. If (A) is true but (R) is false
D. If (A) is false but (R) is false

Answer

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

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that AgI (silver iodide) does not dissolve in NH3 (ammonia).
- This is a factual statement that we need to verify.

2. **Analyzing the Reason**:
- The reason given is that AgI does not dissolve in NH3 due to its ionic character.
- We need to evaluate whether this reasoning is correct.

3. **Solubility of Silver Halides in Ammonia**:
- Generally, silver halides (like AgCl, AgBr) can dissolve in NH3 due to the formation of complex ions (e.g., [Ag(NH3)2]+).
- However, AgI is an exception and does not dissolve in NH3.

4. **Ksp and Ionic Character**:
- The solubility product constant (Ksp) is crucial in determining the solubility of compounds.
- AgI has a lower Ksp compared to other silver halides, indicating that it is less soluble in water and ammonia.

5. **Covalent Character of AgI**:
- The reason AgI does not dissolve in NH3 is not solely due to its ionic character.
- In fact, AgI has significant covalent character because iodine is a large anion with high polarizability.
- According to Fajans' rules, compounds with large anions and small cations tend to have covalent character.

6. **Conclusion**:
- The assertion is correct: AgI does not dissolve in NH3.
- The reason is incorrect: The lack of solubility is not due to ionic character but rather due to covalent character and low Ksp.
- Therefore, the correct answer is that the assertion is true, but the reason is false.

### Final Answer:
- Assertion: True
- Reason: False
- The correct option is that the assertion is true, but the reason is false.