Question

At 60 °C the value of Kw is 9.5 x 10-14.

Considering this, what is the pH of a 5.00 x 10-2 M Ba(OH)2(aq) solution at this temperature?

Answer 1

12

Step-by-step explanation:

Ba(OH)₂ is a strong base that dissociates according to the following equation.

Ba(OH)₂(aq) → Ba²⁺(aq) + 2 OH⁻(aq)

The molar ratio of Ba(OH)₂ to OH⁻ is 1:2. Then, the concentration of OH⁻ is 2 × 5.00 × 10⁻² M = 0.100 M

The ionic product of water (Kw) is:

Kw = 9.5 × 10⁻¹⁴ = [H⁺].[OH⁻] = [H⁺].(0.100)

[H⁺] = 9.5 × 10⁻¹³ M

The pH is

pH = -log [H⁺] = -log 9.5 × 10⁻¹³ = 12