Question

For which of the following compound, equivalent weight is equal to molecular weight?

• A. $H_{2}S{O}_4$
• B. $H_{3}P{O}_2$
• C. $H_{3}P{O}_3$
• D. $H_{3}P{O}_4$

Answer 1

The correct option is B $H_{3}P{O}_2$

For acids, $\text{Equivalent weight}$ $=\frac{\text{Molecular Weight}}{\text{Basicity}}$.

Basicity of an acid can be defined as the number of replaceable hydrogen atoms of that particular acid by a base.

Basicity of $H_{2}S{O}_4$ = 2

Basicity of $H_{3}P{O}_3$ = 2

Basicity of $H_{3}P{O}_4$ = 3

Here, basicity of $H_{3}P{O}_2$ is 1.

Therefore, molecular weight is equal to the equivalent weight.

Hence, option B is correct.