A 25.0 mL sample of 0.150 M hypochlorous acid is titrated with a 0.150 M NaOH solution. What is the pH after 26.0 mL of base is added? The K_aof hypochlorous acid is 3.0 × 10^-⁸. A) 11.47 B) 2.54 C) 7.54 D) 7.51 E) 7.00

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Quizplus · Accepted Answer

The correct answer is A because the pH after 26.0 mL of base is added is 11.47. This can be calculated using the Henderson-Hasselbalch equation: pH = pKa + log([A-]/[HA]), where pKa is the negative logarithm of the acid dissociation constant, [A-] is the concentration of the conjugate base, and [HA] is the concentration of the acid. In this case, the pKa of hypochlorous acid is 3.0 × 10-8, the concentration of the conjugate base (NaOH) is 0.150 M, and the concentration of the acid (HOCl) is 0.150 M - 0.026 M = 0.124 M. Plugging these values into the equation gives a pH of 11.47.

A 250 ML Sample of 0