MDCAT Chemistry MCQ #2218

A 0.1 M solution of a weak monobasic acid has a Ka of 1.0 × 10⁻⁵. What is the pH of this solution?

MDCAT Chemistry MCQ #2218

  1. Question 1

    Q1. A 0.1 M solution of a weak monobasic acid has a Ka of 1.0 × 10⁻⁵. What is the pH of this solution?

    • A) 1
    • B) 2
    • C) 3
    • D) 5

    Answer: 3

    Explanation: For a weak acid, [H+] = √(Ka × C) = √(10⁻⁵ × 0.1) = 10⁻³. Thus pH = 3. Option A assumes the acid is strong and fully dissociates.