Question

What is the molarity of a sodium hydroxide solution if 27.9 mL of this solution reacts exactly with 22.30 mL of 0.253 M sulfuric acid?

Answer 1

n(H₂SO₄) = C_m x V
n(H₂SO₄) = 0.253 M x 0.02230 L = 0.00564 mol
The balanced equation is:
H₂SO₄ + 2NaOH = Na₂SO₄ + 2H₂O
the ratio between H₂SO₄ and NaOH is 1 : 2
n(NaOH) = 0.00564/2 = 0.00282 mol
C_m(NaOH) = n(NaOH)/V(NaOH)
C_m(NaOH) = 0.00282 mol/ 0.0250 L = 0.113 M

Answer: 0.113 M