What is the pH of a solution containing 10^-9 M HClO4?
I know HClO4 is a strong acid so the answer should be -log(10^-9) = 9
But the answer says its 6.996.
What am I missing?
I know HClO4 is a strong acid so the answer should be -log(10^-9) = 9
But the answer says its 6.996.
What am I missing?
-
Remember that pure water contains 1 x 10^-7 M H3O+ which is 100 times more than what's in 10^-9 M HClO4. So the total [H3O+] = [H3O+] from water + [H3O+] from HClO4 = 1 x 10^-7 + 1 x 10^-9 = 1.01 x 10^-7
pH = -log (1.01 x 10^-7) = 6.996
pH = -log (1.01 x 10^-7) = 6.996