Hey mates,
I am having a hard time solving buffer solution problems. I think I understood the idea behind them (governed by Le Chatelier's principle), but when I have to solve an exercise, I just don't get it, especially when we introduce a strong acid (or base). For instance:
1)Calculate the pH of a buffer prepared with the addition of 10mL of HAc 0.1M and 20mL of NaAc 0.1M. Ka = 1.75*10^(-5).

2) We have a buffer with HAc 0.1M and NaAc 0.1M
Calculate the pH of the resulting solution when we introduce HCl (0.05M) to 0.5L of the solution HAc-NaAc.

Question

Hey mates,
I am having a hard time solving buffer solution problems. I think I understood the idea behind them (governed by Le Chatelier's principle), but when I have to solve an exercise, I just don't get it, especially when we introduce a strong acid (or base). For instance:
 1)Calculate the pH of a buffer prepared with the addition of 10mL of HAc 0.1M and 20mL of NaAc 0.1M. Ka = 1.75*10^(-5).

2) We have a buffer with HAc 0.1M and NaAc 0.1M
 Calculate the pH of the resulting solution when we introduce HCl (0.05M) to 0.5L of the solution HAc-NaAc.

vincent-lyon.fr · Answer

Basically, if you introduce an acid into a buffer, the conjugate base in the buffer will react, producing conjugate acid. If you introduce a base, the conjugate acid will react producing the conjugate base.

Use the equation to work out new amounts of conj. acid and conj. base after reaction and work out new pH from new equilibrium.

anonymous · Answer

Thanks for the answer. I worked it out :-)