Question

Solid calcium hydroxide is dissolved in water until the pH of the solution is 10.44. Determine the concentration of the calcium hydroxide in the solution.

Answer 1

Answer:

1.38x10⁻⁴ M

Explanation:

First, we calculate the pOH of the solution, using the given pH:

• pOH = 14 - pH

• pOH = 14 - 10.44

• pOH = 3.56

Now we calculate the concentration of OH⁻, using the pOH:

• pOH = -log[OH⁻]

• [OH⁻] = $10^{-pOH}$ = 2.75x10⁻⁴ M

Following the reaction Ca(OH)₂ → Ca⁺² + 2OH⁻, we divide [OH⁻] by 2 to calculate [Ca(OH)₂]:

• [Ca(OH)₂] = 2.75x10⁻⁴ M / 2

• [Ca(OH)₂] = 1.38x10⁻⁴ M