A solution of 0.220 MM NaOHNaOH is used to titrate 47.0 mLmL of a 0.0324 MM H3PO4H3PO4 solution. What volume, in milliliters, of the NaOHNaOH solution is required?

Question

H3PO4(aq)+3NaOH(aq)→3H2O(l)+Na3PO4(aq)

Answer 1

H₃PO₄ + 3NaOH ==> Na₃PO₄ + 3H₂O ... balanced equation for neutralization reaction

moles H3PO4 present = 47.0 ml x 1 L/1000 ml x 0.0324 mol/L = 0.0015228 moles H₃PO₄

moles NaOH needed = 0.0015228 mol H₃PO₄ x 3 mol NaOH/mol H₃PO₄ = 0.0045684 mol NaOH needed

volume NaOH needed: (x L)(0.220 mol/L) = 0.0045684 mol and x = 0.0208 L = 20.8 mls NaOH