Answer:
pH = 11
Explanation:
The concentration of OH⁻ in pure water is 10⁻⁷ M. If a substance increases OH⁻ concentration by 10⁴, the new concentration will be:
[OH⁻] = 10⁴ x 10⁻⁷ M = 10⁻³M
We can calculate pOH using it's definition:
pOH = -log[OH⁻] = -log (10⁻³) = 3
Then, we can find out pH using the following relation:
pH + pOH = 14
pH = 14 - pOH = 14 -3 = 11
Since pH = 11 is higher than 7, we can confirm that the substance is a base.
