AP Chemistryeasymcq1 pt
At 25 °C, a solution has [H⁺] = 1.0 × 10⁻⁹ M. What is [OH⁻]?
A.1.0 × 10⁻⁹ M (same as the given [H⁺])
B.1.0 × 10⁻¹⁴ M (the value of Kw)
C.1.0 × 10⁻⁷ M (neutral water)
D.1.0 × 10⁻⁵ M
Explanation
Core Concept
Kw = [H⁺][OH⁻] = 1.0 × 10⁻¹⁴ holds for any dilute aqueous solution at 25 °C. Dividing Kw by [H⁺] gives [OH⁻] = 10⁻¹⁴ ÷ 10⁻⁹ = 1.0 × 10⁻⁵ M. Hydroxide exceeds hydronium, confirming the solution is basic.
Correct Answer
D1.0 × 10⁻⁵ M
More Unit 8: Acids and Bases practice questions
- mediumWhich mixture produces a buffer with pH closest to 9.0?
- mediumFor a weak acid, which approximation allows skipping the quadratic?
- mediumWhat is the pH of a solution after 0.0050 mol of HCl is added to 1.0 L of pure water?
- mediumIn the reaction HSO₄⁻ + H₂O ⇌ SO₄²⁻ + H₃O⁺, which species acts as a base?
- easyWhich of the following is the strongest base?
Practice more AP Chemistry questions with full explanations
Practice Unit 8: Acids and Bases Questions →