posted by Anonymous .
In a titration of 35 mL of 0.40 M H3PO4 with 0.30 M KOH solution, what volume (in mL) of KOH solution is needed to reach the last equivalence point (i.e., point in the titration where enough KOH has been added to neutralize all three of the acidic protons in the phosphoric acid)?
3KOH + H3PO4 ==> 3H2O + K3PO4
mols H3PO4 = M x L = ?
Using the coefficients in the balanced equation, convert mols H3PO4 to mols KOH.
M KOH = mols KOH/L KOH. You know M and mols KOH, solve for L KOH.