Saturday, November 20, 2010

Chemistry... pH change? PLEASE help!?

What is the pH change of a 0.280 M solution of citric acid (pKa=4.77) if citrate is added to a concentration of 0.175 M with no change in volume?



If you could PLEASE show how you came to your answer I would appreciate it a lot! Thanks in advance!Chemistry... pH change? PLEASE help!?
Ka = 10^-4.77 =1.70 x 10^-5



1.70 x 10^-5 = x^2 / 0.280-x

x = [H+]= 0.00218 M

pH = 2.66 initial pH



pH = 4.77 + log 0.175/ 0.280= 4.56



change pH = 1.9

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