chemistry
posted by Renee on .
Calculate the pH of a [Acid] M aqueous solution of each of the hydrochloric and acetic acids:
Acid [Acid] pH
HCl 0.10
HC2H3O2 0.10
I know that HCl is just log(0.10) which is 1, but can't get the pH of HC2H3O2.

You need the molarity.
pH = log(H^+) 
1, 2,87

i'm doing this problem too =)
Molarity for both hydrochloric and acetic acids are 0.10. For hydrochloric acid, i used the formula: pH = log (0.10) = 1.
But should we do something else for acetic acid? because its pH is not 1. 
never mind, I found out how to do this =)
(the post above was me by the way).
set up I.C.E. table for the equilibrium expression. Since we know that Ka value for acetic acid is about 1.76 x 10^5, we can solve for x (which is [H+] in this case).
Ka = x^2 / 0.10  x => approximation: 1.76 x 10^5 = X^2 / 0.10. Solve for x. Then use pH = log [H+] to find pH of acetic acid =).