Dear student, you haven't completed the reaction part, but don't worry I know about the reaction of H3PO4 with NaOH, this reaction is generally asked by students.

In the Given Reaction,

NaOH + H3PO4 ----------> NaH2PO4+ H2O

We know that for the Acids, the equivalent weight is equal to the ratio of the molar mass and number of the hydrogen ions of the acid accepted by the base.

∴ In the given reaction,

No. of hydrogen ions replaced by the Base of the Acid = 2

Molar mass of the Acid = 98 g/mole.

∴ Equivalent Weight = 98/2

= 49

Hence, the equivalent weight of the Acid is 49.

All the best

Hope this helps

Hello Lal,

Hope you are doing well.

The molecular weight of phosphoric acid is; (3+31+16*4)gram/mol = 98 gram/mol. Now Equivalent Weight = 98/3 gram/equivalent = 32.67 gram/equivalents.

Hope you are looking for this.

Good luck