Calculate the pH of a solution formed by mixing 100 ml of 0.1 M HCl and 400 ml of 0.05 M NaOH.
- 12.3
- 1.7
- 7.0
- 13.0
📝 Detailed explanation
Moles H⁺ = 0.1 × 0.1 = 0.01 mol.Moles OH⁻ = 0.4 × 0.05 = 0.02 mol.
Excess OH⁻ = 0.02 - 0.01 = 0.01 mol.
Total volume = 0.1 + 0.4 = 0.5 L.
[OH⁻] = 0.01 / 0.5 = 0.02 M.
pOH = -log(0.02) ≈ 1.7.
pH = 14 - 1.7 = 12.3.