The K_aof hydrazoic acid (HN₃) is 1.9 × 10^-⁵at 25.0 °C. What is the pH of a 0.35 M aqueous solution of HN₃?

Question

Quizplus · Accepted Answer

To find the pH, use the formula: pH = -log[H⁺]. First, set up the expression for Kₐ: Kₐ = [H⁺][N₃⁻]/[HN₃]. Assume [H⁺] = x, then Kₐ = x²/(0.35 - x) ≈ x²/0.35. Solve for x: x = √(Kₐ × 0.35) = √(1.9 × 10⁻⁵ × 0.35) ≈ 2.6 × 10⁻³. Therefore, pH = -log(2.6 × 10⁻³) ≈ 2.6.

The Ka of Hydrazoic Acid (HN3) Is 1

The K_aof Hydrazoic Acid (HN₃) Is 1