25.00mL of a sulfuric acid solution of unknown molarity is titrated to the second equivalence point with 20.95mL of 0.243M potassium hydroxide solution

Question

25.00mL of a sulfuric acid solution of unknown molarity is titrated to the second equivalence point with 20.95mL of 0.243M potassium hydroxide solution. What is the concentration of the sulfuric acid solution? Report your answer to 3 decimal places.

Answer 1

First, write the correctly balanced equation for the titration

H2SO4+ 2KOH ==> K2SO4 + H2O ... balanced equation

moles KOH needed = 20.95 ml KOH x 1 L / 1000 ml x 0.243 mol KOH / L = 0.005091 moles KOH

moles H2SO4 present = 0.005091 mol KOH x 1 mol H2SO4 / 2 mol KOH = 0.002545 mols H2SO4

molarity of H2SO4 = 0.002545 mol / 25.00 ml x 1000 ml / L = 0.102 mol/L = 0.102 M