Question

Equivalent mass of $H_{3}P{O}_2$ when it undergoes disproportionation to $P{H}_3$ and $H_{3}P{O}_3$ will be:

• A. $M.w./2$
• B. $M.w./4$
• C. $M.w./24$
• D. $3M.w./4$

Answer 1

The correct option is D $3M.w./4$

$H_{3}P{O}_2+4H^{+}+4e^{-}\to P{H}_3+2H_{2}O{n}_1=4$
$H_{3}P{O}_2+H_{2}O\to H_{3}P{O}_3+2H^{+}+2e^{-}{n}_2=2$
$n-factor=\frac{n_1\times n_2}{n_1+n_2}=\frac{2\times 4}{2+4}=\frac{8}{6}=\frac{4}{3}$
$E.w.=M.w./\frac{4}{3}=\frac{3M.w.}{4}$.