Which buffer solution has the lowest pH (HF has K_a = 7.2 × 10^-4)?

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The pH of a buffer solution is determined by the Henderson-Hasselbalch equation: pH = pKa + log([A-]/[HA]), where [A-] is the concentration of the base form (in this case, F-) and [HA] is the concentration of the acid form (HF). The solution with the lowest pH will have the highest ratio of [HA] to [A-], which is option C, 0.20 M HF and 0.10 M NaF, because it has twice as much acid (HF) as its conjugate base (F-), leading to a lower pH compared to the other options where the ratios are closer to 1 or in favor of the base.

Which Buffer Solution Has the Lowest PH (HF Has Ka

Which Buffer Solution Has the Lowest PH (HF Has K_a