Assertion: Basic radical of V group are precipitated as their carbonates in presence of `NH_(4)OH`.
Reason: `NH_(4)OH` maintains the pH of the solution basic.

Options

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

Explanation

To solve the question, we need to analyze the assertion and the reason provided:

### Assertion:
Basic radicals of V group are precipitated as their carbonates in the presence of NH₄OH.

### Reason:
NH₄OH maintains the pH of the solution basic.

### Step-by-Step Solution:

1. **Understanding V Group Basic Radicals**:
- The V group in qualitative analysis typically includes cations such as Mg²⁺, Ca²⁺, Sr²⁺, and Ba²⁺. These cations can form carbonates.

2. **Role of NH₄OH**:
- Ammonium hydroxide (NH₄OH) is a weak base that can react with certain metal ions to form hydroxides. It is also used to maintain a basic environment in the solution.

3. **Precipitation of Carbonates**:
- In the presence of NH₄OH, the basic radicals of the V group can react with ammonium carbonate (NH₄)₂CO₃ to form their respective carbonates. This is due to the formation of ammonium bicarbonate (NH₄HCO₃) in the solution, which can further react to precipitate the carbonates.

4. **Analyzing the Reason**:
- While it is true that NH₄OH maintains a basic pH, the assertion specifically states that the precipitation of carbonates occurs due to the presence of NH₄OH. The reason does not directly explain why the carbonates precipitate; it merely states that NH₄OH keeps the solution basic.

5. **Conclusion**:
- The assertion is true: V group basic radicals do precipitate as carbonates in the presence of NH₄OH.
- The reason is also true: NH₄OH maintains a basic pH.
- However, the reason does not correctly explain the assertion. Therefore, the correct answer is that both the assertion and reason are true, but the reason is not the correct explanation for the assertion.

### Final Answer:
The correct option is option 4: Both assertion and reason are true, but the reason is not the correct explanation of the assertion.