I love pH questions. You?

Question

the pH of a 0.02M solution of a weak acid was measured to be 5.2. What is the [H+] of this solution? What is the Ka of this solution?

Answer 1

The [H+] is 10 to the power of -5.2 moldm-3.

And the Ka is [H+]squared/0.02.

Now you can work it out.