Posted by Cassie on .
A student titrated a solution containing 3.7066 grams of an unknown triprotic acid to the end point using 28.94 milliliters of 0.3021 M KOH. What is the molar mass of the unknown acid? And write a balanced equation for the reaction.
You don't say to which end point the triprotic acid was titrated. It could be titrated to the first H, the second, or all three. I will assume all three H ions were neutralized.
H3A + 3KOH ==> K3A + 3H2O
moles KOH = M x L = ??
Using the coefficients in the balanced equation, convert mole KOH to moles H3A. That will be ??moles KOH x (1 mole H3A/3 moles KOH) = (1/3) x moles KOH.
Then moles H3A = grams H3A/molar mass H3A. YOu know moles and grams H3A, solve for molar mass.