A weak acid has a strong conjugate base and a strong acid has a weak conjugate base.

Answer

To understand the relationship between weak acids, strong acids, and their conjugate bases, let's break down the concepts step by step.

### Step 1: Definitions
- **Acid**: A substance that donates protons (H⁺ ions).
- **Conjugate Base**: The species that remains after an acid donates a proton.
- **Strong Acid**: An acid that completely dissociates in solution.
- **Weak Acid**: An acid that partially dissociates in solution.

### Step 2: Strong Acid and Weak Conjugate Base
1. **Example of a Strong Acid**: Hydrochloric acid (HCl).
2. **Dissociation**: When HCl dissociates in water, it produces H⁺ and Cl⁻ ions:
\[ \text{HCl} \rightarrow \text{H}^+ + \text{Cl}^- \]
3. **Conjugate Base**: The conjugate base of HCl is Cl⁻.
4. **Stability of Cl⁻**: The Cl⁻ ion is stable and does not readily accept a proton (H⁺) back to form HCl again, which is why it is considered a weak conjugate base.

### Step 3: Weak Acid and Strong Conjugate Base
1. **Example of a Weak Acid**: Acetic acid (CH₃COOH).
2. **Dissociation**: When acetic acid dissociates, it produces H⁺ and CH₃COO⁻ ions:
\[ \text{CH}_3\text{COOH} \rightleftharpoons \text{H}^+ + \text{CH}_3\text{COO}^- \]
3. **Conjugate Base**: The conjugate base of acetic acid is CH₃COO⁻.
4. **Stability of CH₃COO⁻**: The acetate ion (CH₃COO⁻) is less stable compared to Cl⁻ and can readily accept a proton (H⁺) to revert back to acetic acid. This makes it a strong conjugate base.

### Conclusion
- A strong acid like HCl has a weak conjugate base (Cl⁻) because the conjugate base is stable and does not easily re-accept a proton.
- A weak acid like acetic acid has a strong conjugate base (CH₃COO⁻) because the conjugate base is less stable and readily accepts a proton.

### Final Statement
Thus, the statement "A weak acid has a strong conjugate base and a strong acid has a weak conjugate base" is correct.

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