[Olympiad] Calculate the pH of a 0.1 M solution of Cyanic acid (HCN). (Ka = 4.9 × 10⁻¹⁰)
- 2.56
- 4.12
- 5.15
- 7.00
📝 Batafsil tushuntirish
[H⁺] = √(Ka × C) = √(4.9 × 10⁻¹⁰ × 0.1) = √(4.9 × 10⁻¹¹) = 7.0 × 10⁻⁶ M.pH = -log(7.0 × 10⁻⁶) = 6 - 0.845 = 5.155 ≈ 5.16.