Assertion. An aqueous solution of ammonium acetate can act as buffer.
Reason. An aqueous solution of any pure salt acts as a buffer.

Options

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

Explanation

To solve the assertion and reason question, we need to analyze both statements separately.

### Step 1: Analyze the Assertion
The assertion states: "An aqueous solution of ammonium acetate can act as a buffer."

- Ammonium acetate (NH4C2H3O2) is a salt formed from a weak acid (acetic acid, CH3COOH) and a weak base (ammonia, NH3).
- A buffer solution is defined as a solution that can resist changes in pH upon the addition of small amounts of acid or base.
- Since ammonium acetate can dissociate into NH4+ (from the weak base) and CH3COO- (from the weak acid), it can effectively maintain the pH when small amounts of acids or bases are added.

**Conclusion for Assertion**: The assertion is true.

### Step 2: Analyze the Reason
The reason states: "An aqueous solution of any pure salt acts as a buffer."

- A pure salt does not necessarily act as a buffer. A buffer solution specifically requires a weak acid and its conjugate base (or a weak base and its conjugate acid) to maintain pH.
- Pure salts, such as sodium chloride (NaCl), do not provide this capability because they are formed from strong acids and strong bases, which do not have the ability to resist changes in pH.

**Conclusion for Reason**: The reason is false.

### Final Conclusion
Since the assertion is true and the reason is false, the correct answer is that the assertion is true, but the reason is false.

### Answer: Option 3

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