Aqueous solution of `HNO_(3),CH_(3),CH_(3)COOH`, and `CH_(3)COOK` of identical concentrations are given. The pair (s) of the solution which may form a buffer upon mixing is (are):

Options

A. `NaOH` and `CH_(3)COOH`
B. `HNO_(3)` and `CH_(3)COOK`
C. `CH_(3)COOH` and `CH_(3)COOK`
D. `HNO_(3)+CH_(3)COOH`

Explanation

To determine which pairs of the given solutions can form a buffer upon mixing, we need to understand the concept of buffer solutions. A buffer solution is typically made from a weak acid and its conjugate base or a weak base and its conjugate acid.

Let's analyze the given solutions:

1. **HNO₃** - This is a strong acid.
2. **CH₃COOH** - This is acetic acid, a weak acid.
3. **CH₃COOK** - This is potassium acetate, which is a salt derived from a weak acid (acetic acid) and a strong base (potassium hydroxide).

Now, we will evaluate each pair:

### Step 1: Pair HNO₃ and CH₃COOK
- HNO₃ is a strong acid.
- CH₃COOK is a salt of a weak acid (CH₃COOH) and a strong base (KOH).
- Mixing a strong acid with the salt of a weak acid does not form a buffer because we do not have a weak acid and its conjugate base in the mixture.

**Conclusion**: This pair does not form a buffer.

### Step 2: Pair CH₃COOH and CH₃COOK
- CH₃COOH is a weak acid.
- CH₃COOK is the salt of its conjugate base (CH₃COO⁻).
- Mixing a weak acid with its salt (conjugate base) will form a buffer solution.

**Conclusion**: This pair forms a buffer.

### Step 3: Pair HNO₃ and CH₃COOH
- HNO₃ is a strong acid.
- CH₃COOH is a weak acid.
- Mixing two acids (one strong and one weak) does not provide a buffer system, as we do not have a conjugate base present.

**Conclusion**: This pair does not form a buffer.

### Step 4: Pair CH₃COOH and HNO₃
- Similar to the previous analysis, this pair consists of a strong acid (HNO₃) and a weak acid (CH₃COOH), which cannot form a buffer.

**Conclusion**: This pair does not form a buffer.

### Final Summary
The pairs that can form a buffer upon mixing are:
- **CH₃COOH and CH₃COOK**