Question

A 25.0-mL sample of an H2SO4 solution requires 50.0 mL of 0.150 M NaOH to completely react with the H2SO4. What was the concentration (molarity, M) of the H2SO4 solution?
H2SO4(aq) + 2 NaOH(aq) à Na2SO4(aq) + 2 H2O(l)

Answer 1

V( H₂SO₄) = 25.0 mL in liters = 25.0 / 1000 = 0.025 L
 M(H₂SO₄) = ?

V(NaOH) = 50.0 mL = 50.0 / 1000 = 0.05 L 
M(NaOH) = 0.150 M

number of moles NaOH :

n = M x V

n = 0.150 x  0.05 

n = 0.0075 moles of NaOH 

H₂SO₄(aq) + 2 NaOH(aq) = Na₂SO₄(aq) + 2 H₂O(l)

1 mole H₂SO₄ ---------- 2 mole NaOH
? mole H₂SO₄ ---------- 0.0075 moles NaOH

moles = 0.0075 * 1 / 2

= 0.00375 moles of H₂SO₄

M(H₂SO₄) = n / V

M = 0.00375 /  0.025

= 0.15 M

hope this helps!