Question

When [OH-] changes from 10-9 to 10-11 in a solution: Kw = [H+][OH-] What happens to [H+]?

a. Increases
b. decreases
c. remains constant

Answer 1

Kw is a constant number under same temperature. So when [OH-] decrease from 10^-9 to 10^-1, the [H+] will increase. So the answer is a. increases.

Answer 2

[H⁺] increases

Step-by-step explanation:

Kw = [H⁺][OH⁻]

[OH⁻] = 10⁻⁹

Kw = 1 x 10⁻¹⁴

[H⁺] = Kw / [OH⁻] = 1 x 10⁻¹⁴ / 10⁻⁹= 10⁻⁵

[OH⁻] = 10⁻¹¹

Kw = 1 x 10⁻¹⁴

[H⁺] = Kw / [OH⁻] = 1 x 10⁻¹⁴ / 10⁻¹¹= 10⁻³

As the concentration of OH⁻decreases, the concentration of H⁺ increases.