A pH 4.88 buffer was prepared by dissolving 0.10 mol of benzoic acid (Ka = 6.3 × 10^-5) and 0.50 mol of sodium benzoate in sufficient pure water to form a 1.00 L solution. To a 70.0 mL aliquot of this solution was added 2.00 mL of 2.00 M HI solution. What was the pH of the new 72.0 mL solution? A) 2.84 B) 3.16 C) 3.36 D) 4.65 E) 4.90

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Quizplus · Accepted Answer

The pH of the buffer solution is calculated using the Henderson-Hasselbalch equation. After adding HI, the moles of benzoate decrease and benzoic acid increase, but the buffer capacity maintains the pH close to the original value.

A PH 488 Buffer Was Prepared by Dissolving 0