Calculate pH of 1.00x10-8 M HClO4 Solution

[Oblivion77]

Homework Statement

The pH of a 1.00x10-8 M solution of HClO4 is

Homework Equations

-log(H3O+)

The Attempt at a Solution

I thought I could just do -log(1.00x10^8) = 8, but the answer is actually 6.98. Why?

Does it have anything to do with it being a strong acid?

 

[sumzup]

Since the concentration is extremely dilute and is < 1e-7, a phenomenon known as autoionization of water takes place...check out Example 3 under Strong Acids on http://www.science.uwaterloo.ca/~cchieh/cact/c123/stacids.html" for how to solve.

 

[Oblivion77]

Since the concentration is extremely dilute and is < 1e-7, a phenomenon known as autoionization of water takes place...check out Example 3 under Strong Acids on http://www.science.uwaterloo.ca/~cchieh/cact/c123/stacids.html" for how to solve.

thanks a lot.