Dibasic phosphate `(HPO_(4)^(2-))` is a buffer against

Options

A. Toxic chemicals
B. Strong acids
C. Strong base
D. Weak bases and acids.

Answer

To determine what dibasic phosphate `(HPO₄²⁻)` acts as a buffer against, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Buffers**:
- Buffers are solutions that resist changes in pH when small amounts of acid or base are added. They typically consist of a weak acid and its conjugate base or a weak base and its conjugate acid.

2. **Identifying Dibasic Phosphate**:
- Dibasic phosphate is represented as `HPO₄²⁻`. It is derived from phosphoric acid `(H₃PO₄)`, which is a strong acid. When phosphoric acid ionizes, it forms `H₂PO₄⁻` and `HPO₄²⁻`.

3. **Buffer Formation**:
- Since `HPO₄²⁻` is the conjugate base of `H₂PO₄⁻`, it can act as a buffer. In this case, `HPO₄²⁻` can react with strong acids to neutralize them, and it can also react with strong bases.

4. **Analyzing the Options**:
- The options given are: toxic chemicals, strong acids, strong bases, and weak bases and acids.
- Since `HPO₄²⁻` is formed from a strong acid, it will primarily act as a buffer against strong bases.

5. **Conclusion**:
- Therefore, the final answer is that dibasic phosphate `(HPO₄²⁻)` is a buffer against **strong bases**.

### Final Answer:
Dibasic phosphate `(HPO₄²⁻)` is a buffer against **strong bases**.