What is the pH of a solution made by dissolving 2.16 g of sodium benzoate (NaC₆H₅CO₂) in a sufficient volume of 0.033 M benzoic acid solution to prepare 500.0 mL of buffer? [Ka for benzoic acid is 6.3 × 10^-5] A) 4.16 B) 4.37 C) 4.64 D) 5.77 E) 6.30

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Quizplus · Accepted Answer

The correct answer is A because the pH of a buffer solution can be calculated using the Henderson-Hasselbalch equation: pH = pKa + log([A-]/[HA]), where pKa is the dissociation constant of the weak acid, [A-] is the concentration of the conjugate base, and [HA] is the concentration of the weak acid. In this case, the weak acid is benzoic acid and the conjugate base is sodium benzoate. The concentration of benzoic acid can be calculated from the given volume and concentration of the benzoic acid solution, and the concentration of sodium benzoate can be calculated from the given mass and molar mass of sodium benzoate. Plugging these values into the Henderson-Hasselbalch equation gives a pH of 4.16.

What Is the PH of a Solution Made by Dissolving