Question

A solution at 25 degrees Celsius is 1.0 × 10–5 M H3O+. What is the concentration of OH– in this solution? 1.0 × 10–5 M OH– 1.0 × 10–14 M OH– 1.0 × 105 M OH– 1.0 × 10–9 M OH–

Answer 1

Answer:

1.0 x 10⁻⁹ M OH⁻.

Explanation:

∵ [H₃O⁺][OH⁻] = 10⁻¹⁴.

[H₃O⁺] = 1.0 x 10⁻⁵ M.

∴ [OH⁻] = 10⁻¹⁴/[H₃O⁺] = 10⁻¹⁴/(1.0 x 10⁻⁵ M) = 1.0 x 10⁻⁹ M.

So, the right choice is: 1.0 x 10⁻⁹ M OH⁻.