Which statements is//are correct?

Options

A. Compared to a strong acid, a weak acid titration with base starts at a higher `pH`.
B. Compared to a strong base, a weak base titration ends at a lower `pH`.
C. In both (a) and (b) titration curve is shortened at each end.
D. For titration of a weak base, the neraly vertical portion of the curve would be insufficient for an effective titration.

Answer

To determine which statements are correct regarding the titration of acids and bases, we will analyze each statement step by step.

### Step-by-Step Solution:

1. **Understanding Titration Curves**:
- Titration curves show how the pH of a solution changes as a titrant (acid or base) is added.
- Strong acids and bases dissociate completely in solution, while weak acids and bases do not.

2. **Statement 1**: "Compared to a strong acid, a weak acid titration with base starts at a higher pH."
- **Analysis**:
- A strong acid, like HCl, will have a low initial pH (around 1-2) because it completely dissociates.
- A weak acid, like acetic acid, will have a higher initial pH (around 3-4) because it does not dissociate completely.
- **Conclusion**: This statement is **true**.

3. **Statement 2**: "Compared to a strong base, a weak base titration ends at lower pH."
- **Analysis**:
- A strong base, like NaOH, will have a high final pH (around 13-14) because it completely dissociates.
- A weak base, like ammonia, will have a lower final pH (around 10-11) because it does not dissociate completely.
- **Conclusion**: This statement is **true**.

4. **Statement 3**: "Both A and B titration curves are shortened at each end."
- **Analysis**:
- The titration curves for both strong and weak acids/bases do show a more gradual change at the beginning and end, indicating that the pH does not change as rapidly as in the middle of the titration.
- **Conclusion**: This statement is **true**.

5. **Statement 4**: "For titration of weak base, the nearly vertical position of the curve would be insufficient for an effective titration."
- **Analysis**:
- A nearly vertical position in a titration curve indicates a sharp change in pH, which is effective for determining the endpoint of a titration.
- Therefore, a nearly vertical position would actually be sufficient for effective titration.
- **Conclusion**: This statement is **false**.

### Final Conclusion:
- Statements 1, 2, and 3 are correct.
- Statement 4 is incorrect.