It takes 45ml of 1.2M KOH to neutralize 60ml of H3PO4 solution. What is the molarity? H3PO4+3KOH=K3PO4+3H2O?

n(KOH) = (1.2 mmol/mL) × (45 mL) = 54 mmol

H₃PO₄ + 3KOH → K₃PO₄ + 3H₂O
n(H₃PO₄) : n(KOH) = 1 : 3
n(H₃PO₄) : (54 mmol) = 1 : 3
n(H₃PO₄) = (54 mmol) × (1/3) = 18 mmol

Molarity of H₃PO₄ = (18 mmol) / (60 mL) = 0.3 M