Question

The normality of 0.3 M phosphorous acid $\left(H_{3}P{O}_3\right)$, phosphoric acid $\left(H_{3}P{O}_4\right)$ and boric acid $\left(H_{3}B{O}_3\right)$ respectively are:

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

Answer 1

The correct option is C 0.6, 0.9, 0.3

n-factor for $H_{3}P{O}_3=2$
(as only 2 hydrogen atoms are replaceable)
Normality = molarity $\times$ n-factor
$=0.3\times 2=0.6$ N

n-factor for $H_{3}P{O}_4=3$
Normality = molarity $\times$ n-factor
$=0.3\times 3=0.9$ N

n-factor for $H_{3}B{O}_3=1$
Normality = molarity $\times$ n-factor
$=0.3\times 1=0.3$ N