Chemistry
Chemistry
Problem
A solution containing equal molar amounts of NH and NHCl at 25 °C receives a few drops of 0.10 M NaOH, and the volume change is negligible. Which statement best describes the resulting pH change? a) The pH remains exactly the same because buffers completely prevent any pH change. b) The pH increases slightly because the added is largely neutralized. c) The pH increases dramatically because the remains unreacted in solution. d) The pH decreases slightly because the added converts to .Intuitive explanation
This is a buffer problem—you have a weak base and its conjugate acid in roughly equal amounts, which resists pH change. The key insight is that added strong base (NaOH) will react with the acidic component () rather than the basic component, converting some conjugate acid into more conjugate base. Since you're adding only a few drops to a solution already rich in buffer, the ratio of base to acid changes only slightly, so the pH shifts only modestly upward.
Intuitive explanation
This is a buffer problem—you have a weak base and its conjugate acid in roughly equal amounts, which resists pH change. The key insight is that added strong base (NaOH) will react with the acidic component () rather than the basic component, converting some conjugate acid into more conjugate base. Since you're adding only a few drops to a solution already rich in buffer, the ratio of base to acid changes only slightly, so the pH shifts only modestly upward.