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A weak base is titrated with 1.0 mol L⁻¹ aqueous HCl - HSC - SSCE Chemistry - Question 8 - 2020 - Paper 1
Question 8
A weak base is titrated with 1.0 mol L⁻¹ aqueous HCl. The pH curve is shown. At which pH value would the solution be most effective as a buffer? A. 5 B. 7 C. 8 D. ... show full transcript
Worked Solution & Example Answer:A weak base is titrated with 1.0 mol L⁻¹ aqueous HCl - HSC - SSCE Chemistry - Question 8 - 2020 - Paper 1
Step 1
At which pH value would the solution be most effective as a buffer?
Answer
The pH at which a solution is most effective as a buffer corresponds to the pKa of the weak acid/base pair involved in the titration. This typically occurs near the equivalence point where the concentrations of the weak acid and its conjugate base are approximately equal.
From the titration curve, the pH appears to level out around 9, indicating the presence of the weak base and its conjugate base. Therefore, the solution would be most effective as a buffer at:
Answer: D. 9