posted by Mike Jones .
You have a solution of 0.15M Ba(OH)2 and a solution of H2SO4 whose concentration you want to determine. You start with 25 ml H2SO4 in the Erlenmeyer and titrate in the Ba(OH)2. At the end of the titration, you find that you have used 20.4 ml Ba(OH)2 and an additional 2.2 ml H2SO4 because you hadto back-titrate.
How many moles of OH- are in 20.4 ml of a 0.15 Ba(OH)2 solution?
mols Ba(OH)2 = M x L = ?
mols OH^- = twice that of Ba(OH)2