What is the equivalent mass of \(H_3PO_4\) in the reaction

\(Ca(OH)_2 + H_3PO_4 \longrightarrow CaHPO_4 + 2H_2O\)

49

The correct answer is option 4. 49.

As in this reaction only two hydrogen atoms are replaced so its equivalent mass will be given by the following expression:

Equivalent mass of \(H_3PO_4\)

\(= \frac{\text{Molecular mass of }H_3PO_4}{2}\)

\(= \frac{98}{2} = 49\)