A 1.00 L buffer solution is 0.250 mol L^-1 in HF and 0.250 mol L^-1 in NaF. Calculate the pH of the solution after the addition of 100.0 mL of 1.00 mol L^-1 HCl. The K_a for HF is 3.5 × 10^-4. A) 3.09 B) 4.11 C) 3.82 D) 3.46 E) 2.78

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Quizplus · Accepted Answer

The correct answer is A because the pH of the solution after the addition of 100.0 mL of 1.00 mol L-1 HCl 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 HF is 3.5 × 10-4, [A-] = 0.250 mol L-1, and [HA] = 0.250 mol L-1. Substituting these values into the Henderson-Hasselbalch equation gives:pH = 3.5 × 10-4 + log(0.250/0.250) = 3.09

A 100 L Buffer Solution Is 0