Question

What is the molarity of a NaOH solution if 15.0 mL of the solution is neutralized by 38.5 mL 0.150 M H3PO4 solution?

Answer 1

The solution for this problem is:
Look for the moles of NaOH which is 0.0385 L x 0.150 M = 0.00578
H3PO4 + 3 NaOH = Na3PO4 + 3 H2O
moles H3PO4 = 0.00578 / 3 = 0.00193
M of H3PO4 = 0.00193 mol / 0.0150 L= 0.128 is the molality we are looking for in this problem.