Question

Assertion: In the reaction: $2NaOH+H_{3}P{O}_4\to N{a}_{2}HP{O}_4+2H_{2}O$

The Equivalent weight of $H_{3}P{O}_4$ is $\frac{M}{3}$, where M is its molar mass
Reason: Equivalent weight $=\frac{\text{Molar mass}}{\text{n-factor}}$

• A. Both the assertion and reason are true, and the reason is the correct explanation of assertion
• B. Both assertion and reason are true, and R is not the correct explanation of assertion
• C. The assertion is true, but reason is false
• D. The assertion is false, but reason is true

Answer 1

The correct option is D The assertion is false, but reason is true

As per the reaction, the number of replaceable $H^{+}$ ions is 2. Hence, the n-factor is 2.
Therefore, the equivalent mass of $H_{3}P{O}_4$ for this particular reaction = $\frac{\text{Molar mass}}{2}$
So, the assertion is false, and the reason is true.