The equation for the reaction is
#"H"_2"SO"_4 + "Ca(OH)"_2 → "CaSO"_4 + 2"H"_2"O"#.
1. Calculate the moles of #"H"_2"SO"_4#
#"Moles of H"_2"SO"_4 = "0.088 61" color(red)(cancel(color(black)("L H"_2"SO"_4))) ×( "0.400 mol H"_2"SO"_4)/(1 color(red)(cancel(color(black)("L H"_2"SO"_4)))) = "0. 035 44 mol H"_2"SO"_4#
2. Calculate the moles of #"Ca(OH)"_2#
#"Moles of Ca(OH)"_2 = "0.035 44" color(red)(cancel(color(black)("mol H"_2"SO"_4))) × ("1 mol Ca(OH)"_2)/(1 color(red)(cancel(color(black)("mol H"_2"SO"_4)))) = "0.035 44 mol NaOH"#
3. Calculate the molarity of the #"Ca(OH)"_2#
#"Molarity" = "moles"/"litres" = "0.035 44 mol"/("0.040 00 L") = "0.886 mol/L"#
