Final answer:
To calculate the hydronium ion concentration ([H₃O⁺]) when given the hydroxide ion concentration ([OH⁻] = 4.47 × 10⁻⁵ M), use the water ion-product constant to find [H₃O⁺] = (1.0 × 10⁻¹⁴ M) / [OH⁻], which yields approximately 2.24 × 10⁻¹⁴ M for this basic solution.
Step-by-step explanation:
To calculate the hydronium ion concentration ([H₃O⁺]) of a milk of magnesia solution with a given hydroxide ion concentration ([OH⁻] = 4.47 × 10⁻⁵ M), we use the ion-product constant for water, Kw, which is 1.0 × 10⁻¹⁴ at 25 °C. The relationship is given by Kw = [H₃O⁺]×[OH⁻], and by rearranging the equation we get [H₃O⁺] = Kw / [OH⁻].
Plugging in the values:
[H₃O⁺] = (1.0 × 10⁻¹⁴ M) / (4.47 × 10⁻⁵ M)
≈ 2.24 × 10⁻¹⁴ M
In this case, the result indicates that milk of magnesia is a basic solution, as the [H₃O⁺] is less than [OH⁻].