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Question

You titrated 40.00mL of an unknown H2SO4(aq) solution to the second equivalence point with 33.17mL of 0.389M NaOH(aq). What is the concentration of the H2SO4(aq) solution?

Answer 1

First, write the balanced equation for the titration of H2SO4 to the 2nd equivalence point

H2SO4 + 2NaOH ==> Na2SO4 + 2H2O

Next, find the mols NaOH used

33.17 ml NaOH x 1 L / 1000 ml x 0.389 mol/L = 0.0129 mol NaOH used

Next, calculate mols H2SO4 present

0.0129 mol NaOH x 1 mol H2SO4 / 2 mol NaOH = 0.00645 mol H2SO4

Finally, calculate the concentration (mol/L) of H2SO4

0.00645 mol H2SO4 / 40.00 ml x 1000 ml / L = 0.161 mol H2SO4 / L = 0.161 M H2SO4