A : Solution of `CH_3COONH_4` is a buffer solution
R: `H^+` ion added will be consumed by `CH_3COO^-` ion and `OH^-` ion added will be consumed by `NH_4^+` ion.

Options

A. If both Assertion & Reason are true and the reason in the corret explanation of the assertion, then mark
B. If both assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark
C. If Assertion is true statement but Reason is false then mark
D. If both Assertion and Reason are false statements , then mark

Answer

To solve the question regarding the assertion and reason about the buffer solution of CH₃COONH₄, we will break it down step by step.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that the solution of CH₃COONH₄ is a buffer solution.
- A buffer solution is defined as a solution that can resist changes in pH upon the addition of small amounts of acids or bases.

2. **Analyzing CH₃COONH₄**:
- CH₃COONH₄ (Ammonium acetate) is a salt formed from a weak acid (acetic acid, CH₃COOH) and a weak base (ammonia, NH₃).
- When dissolved in water, it dissociates into CH₃COO⁻ (acetate ion) and NH₄⁺ (ammonium ion).

3. **Buffer Action**:
- In a buffer solution, the weak acid and its conjugate base (or weak base and its conjugate acid) work together to neutralize added acids or bases.
- In this case:
- If H⁺ ions are added to the solution, they will react with the acetate ion (CH₃COO⁻) to form acetic acid (CH₃COOH), which is a weak acid. This minimizes the increase in acidity.
- If OH⁻ ions are added, they will react with the ammonium ion (NH₄⁺) to form ammonia (NH₃) and water, which helps to minimize the increase in basicity.

4. **Understanding the Reason**:
- The reason states that H⁺ ions added will be consumed by CH₃COO⁻ ions and OH⁻ ions added will be consumed by NH₄⁺ ions.
- This statement is true as it describes the mechanism by which the buffer solution maintains its pH.

5. **Conclusion**:
- Both the assertion and reason are true, and the reason correctly explains why the assertion is true.
- Therefore, the correct answer is that both the assertion and reason are true, and the reason is the correct explanation of the assertion.

### Final Answer:
- The correct option is: **If both assertion and reason are true, reason is the correct explanation of the assertion.**