Question

The normality of $0.3$M phosphoric acid is

• A. $0.1$
• B. $0.9$
• C. $0.3$
• D. $0.6$

Answer 1

The correct option is B $0.9$

$\left(H_{2}P{O}_4\right)$ is a tribasic acid and hence its equivalent weight
$=\frac{Molecularmass}{3}$
$=\frac{M}{3}$
Molecular mass $\times$ molarity $=$ Equivalent mass $\times$ normality
$M\times 0.3=\frac{M}{3}\times N$
$\therefore N=\frac{M\times 0.3\times 3}{M}$
$=0.9N$