What is the molarity of H2SO4(aq)

Question

A 32.5 mL solution of H2SO4(aq) of unknown concentration was titrated with 0.12 M NaOH(aq).

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

If it takes 21.4 mL of NaOH(aq) to reach the equivalence point of the titration, what is the molarity of H2SO4(aq)? For your answer, only type in the numerical value with two significant figures. Do NOT include the unit.

Answer 1

From the balanced equation we see the mole ratio of NaOH to H2SO4 is 2:1. We will use this in our dimensional analysis below.

moles NaOH used = 0.12 mol/L x 0.0214 L = 0.002568 moles

moles H2SO4 present = 0.002568 mol NaOH x 1 mol H2SO4 / 2 mol NaOH = 0.001284 moles

Molarity H2SO4 = moles/liter = 0.001284 mol/0.0325 L = 0.0395 M = 0.040 M