Question

What volume of 0.114 M NaOH are needed to neutralize 25.0 mL of 0.250 M H3PO4?

Answer 1

H3PO4 + 3NaOH ==> Na3PO4 + 3H2O

mols H3PO4 = M x L = ?
Using the coefficients in the balanced equation, convert mols H3PO4 to mols NaOH. That will be
mols NaOH = 3 * mols H3PO4.
Then M NaOH = mols NaOH/L NaOH. YOu know mols NaOH and M NaOH, solve for L NaOH and convert to mL if needed.