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The diagram shows a pH curve produced by adding a strong alkali to a weak acid - AQA - A-Level Chemistry - Question 22 - 2017 - Paper 3
Question 22
The diagram shows a pH curve produced by adding a strong alkali to a weak acid. Which point on the curve represents a solution that can act as a buffer? A B C D
Worked Solution & Example Answer:The diagram shows a pH curve produced by adding a strong alkali to a weak acid - AQA - A-Level Chemistry - Question 22 - 2017 - Paper 3
Step 1
Which point on the curve represents a solution that can act as a buffer?
Answer
To determine which point can act as a buffer, we look for a region on the pH curve where both a weak acid and its conjugate base are present. This is typically seen in the flat part of the curve, indicating that the solution can resist changes in pH upon the addition of small amounts of acid or base.
In the provided diagram, point B is located in a region where the pH is relatively stable, suggesting a buffer solution is present there. Therefore, the answer is:
B.