Two buffer solutions are prepared using acetic acid and sodium acetate. Solution A contains 20.0 g of acetic acid (CH₃COOH) and 5.0 g of sodium acetate CH₃COONa). Solution B contains 10.0 g of acetic acid and 25.0 g of sodium acetate. What is the difference between the pH values of these two solutions? For acetic acid, K_a = 1.8 × 10⁻⁵. A)0.0 B)1.0 C)2.0 D)2.3 E)4.6

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Quizplus · Accepted Answer

The pH difference between the two solutions can be calculated using the Henderson-Hasselbalch equation: pH = pKa + log([A-]/[HA]), where [A-] is the concentration of the acetate ion and [HA] is the concentration of acetic acid. Since both solutions use the same acid and its salt, the pKa value remains constant, and the ratio of [A-] to [HA] determines the pH. The difference in the ratios of sodium acetate to acetic acid between the two solutions results in a pH difference, but the exact numerical difference in pH depends on these ratios rather than the absolute amounts of substances. However, without calculating the exact concentrations and applying the Henderson-Hasselbalch equation, we cannot determine the precise pH difference from the information given. The correct choice is based on understanding that the pH difference is due to the difference in the ratios of the components in the buffer solutions.

Two Buffer Solutions Are Prepared Using Acetic Acid and Sodium