Chemistry chemi$try

Question

200.0L of a solution of H2SO4 of an unknown concentration is titrated with a 2.4-M solution of KOH. If it takes 124mL of KOH to reach the endpoint, what is the concentration of H2SO4?

Answer 1

Balanced Reaction: H₂SO₄ + 2 KOH → K₂SO₄ + 2 H₂O

Use volume and Molarity of KOH to determine moles of KOH.

mol KOH = 2.4 mol/L x 124 mL x (1 L / 1000 mL) = 0.2976 mol KOH

From the balanced reaction, it takes 2 moles of KOH to neutralize 1 mole of H₂SO₄.

mol H₂SO₄ = 0.2976 mol KOH x (1 mol H₂SO₄ / 2 mol KOH) = 0.1488 mol H₂SO₄

Molarity of H₂SO₄ = mol / L = 0.1488 mol / 200.0 L = 7.4 x 10^-4 M (rounded to 2 significant figures)