Question

The equivalent weight of phosphoric acid $\left( H _{3} PO _{4}\right)$ in the reaction: $NaOH + H _{3} PO _{4} \rightarrow NaH _{2} PO _{4}+ H _{2} O$ is

• A. 25
• B. 49
• C. 59
• D. 98

Answer 1

Answer: (D)

98

Answer 2

The given reaction is : $NaOH + H _{3} PO _{4} \rightarrow NaH _{2} PO _{4}+ H _{2} O$ Molecular mass of $H _{3} PO _{4}$ is $98 .$ As there is only one electron change involved therefore, equivalent weight of $H _{3} PO _{4}$ in this reaction is, $\frac{98}{1}=98$