How many grams of 20% NaOH solution are needed to react with 100 ml of 0.5 M H₂SO₄?
- 20 g
- 10 g
- 40 g
- 5 g
📝 Detailed explanation
H₂SO₄ + 2NaOH → Na₂SO₄ + 2H₂O.n(H₂SO₄) = 0.1 L * 0.5 M = 0.05 mol.
n(NaOH) needed = 0.05 * 2 = 0.1 mol.
Mass pure NaOH = 0.1 * 40 = 4 g.
Mass 20% solution = 4 / 0.2 = 20 g.