Question

u4) If 46.2 mL of 2.50 M NaOH is required to neutralize 25.00 mL of a phosphoric acid, H_3PO_4, solution, what is the molarity of the phosphoric acid?

        3 NaOH + H_3 PO_4→ 〖Na〗_3 PO_4  + 3 H_2 O

Answer 1

Moles of NaOH $=0.0462×2.50=0.1155moles$

Moles is $H_3PO_4=\frac{0.1155}{3}=0.0385$

Molarity $=\frac{0.0385}{0.025}=1.54M$