Calculate [OH⁻] of a lemon juice solution at 25°C with a [H⁺] = 5.7 × 10⁻⁴ M.

• A. 5.7 × 10¹⁰ M
• B. 4.7 × 10⁻¹¹ M
• C. 2.7 × 10⁻¹⁸ M
• D. 1.8 × 10⁻¹¹ M

Answer: (D)

Verified step by step guidance

1. Understand that Kw is the ion product of water, which is the product of the concentrations of hydrogen ions [H⁺] and hydroxide ions [OH⁻] in water: Kw = [H⁺][OH⁻].
2. Recognize that the pH of a solution is related to the concentration of hydrogen ions by the formula: pH = -log[H⁺].
3. Use the given pH value of 7.083 to find the concentration of hydrogen ions [H⁺] by rearranging the pH formula: [H⁺] = 10^(-pH).
4. Since pure water is neutral, the concentration of hydroxide ions [OH⁻] is equal to the concentration of hydrogen ions [H⁺]. Therefore, [OH⁻] = [H⁺].
5. Calculate Kw by multiplying the concentrations of [H⁺] and [OH⁻] obtained from the previous steps: Kw = [H⁺] × [OH⁻].