Chemistry : Asid and bes

Question

In an experiment, 25 cm² of 0.1 mol dm^-3 sulphuric acid is needed to neutralise 25 cm³ of sodium hydroxide solution. Calculate the concentration of sodium hydroxide solution use in this experiment.

Answer 1

It would be 25cm³ (not cm²) of sulphuric acid (H₂SO₄).

H₂SO₄ + 2 NaOH ==> Na₂SO₄ + 2H₂O ... balanced equation for the reaction

25cm³ H₂SO₄ x 1 L /1000 cm³ x 0.10 mol/L = 0.0025 mols H₂SO₄ present

mols NaOH needed = 0.0025 mol H₂SO₄ x 2 mols NaOH / mol H₂SO₄ = 0.0050 mols NaOH needed

Concentration of NaOH: 0.0050 mols NaOH / 0.025 L = 0.20 M NaOH