Which one of the following pairs of solution is not an acidic buffer?

Options

A. `HClO_(4)` and `NaClO_(4)`
B. `CH_(3)COOH` and `CH_(3)COONa`
C. `H_(2)CO_(3)` and `Na_(2)CO_(3)`
D. `H_(3)PO_(4)` and `Na_(3)PO_(4)`

Explanation

To determine which pair of solutions is not an acidic buffer, we need to understand what constitutes an acidic buffer. An acidic buffer is typically made up of a weak acid and its conjugate base (usually in the form of a salt).

### Step-by-Step Solution:

1. **Identify the Components of Each Pair**:
- Look at the given pairs of solutions and identify if they consist of a weak acid and its salt (conjugate base).

2. **Analyze Each Option**:
- **Option A**: HClO4 (Perchloric Acid) and its salt. HClO4 is a strong acid and does not form an acidic buffer.
- **Option B**: A weak acid (e.g., acetic acid) and its salt (e.g., sodium acetate). This is an acidic buffer.
- **Option C**: Carbonic acid (H2CO3) and its salt (e.g., sodium bicarbonate). This is also an acidic buffer.
- **Option D**: Phosphoric acid (H3PO4) and its salt (e.g., sodium phosphate). This is another acidic buffer.

3. **Conclusion**:
- From the analysis, only **Option A (HClO4)** does not form an acidic buffer because it is a strong acid and does not consist of a weak acid and its salt.

### Final Answer:
**Option A (HClO4)** is not an acidic buffer.