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Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: FarazKhan1982 on October 13, 2007, 10:45:55 PM

Title: Buffer solution
Post by: FarazKhan1982 on October 13, 2007, 10:45:55 PM
You have a 100.0 ml of a 1.0 Formal concentration buffer solution that has 2 ionizable groups
(pKa 1 = 6.2 and pKa 2 = 9.5). The solution has a pH of 6.8. If you add 60 mL of 1.0 M HCl what would this change the pH too?

i think Pka 1 = 6.2 we are interested in because it close to pH of 6.8, but if u add strong acid like HCl, the pH should go down.
Title: Re: Buffer solution
Post by: Borek on October 14, 2007, 03:47:32 AM
You are completely off.

First of all - which pKa constant are we interested in? Do we have to take both into account, nor not? Why?

Second: what ions are pesent in the solution of buffer? In what ratio? What happens when you add strong acid?
Title: Re: Buffer solution
Post by: FarazKhan1982 on October 14, 2007, 11:46:09 AM
i think Pka 1 = 6.2 we are interested in because it close to pH of 6.8, but if u add strong acid like HCl, the pH should go down.