Question

Identity the compound in which phosphorus exists in the oxidation state of +1.

• A. Phosphonic acid $\left(H_{3}P{O}_3\right)$
• B. Phosphinic acid $\left(H_{3}P{O}_2\right)$
• C. Pyrophosphorus acid $\left(H_4{P}_2{O}_5\right)$
• D. Orthophosphoric acid $\left(H_{3}P{O}_4\right)$

Answer 1

Answer: (B)

Phosphinic acid $\left(H_{3}P{O}_2\right)$

The oxidation state of $P$ atom in phosphonic acid $H_{3}P{O}_3$ is:

$3+x-6=0$

$x=+3$.

The oxidation state of $P$ atom in phosphinic acid $H_{3}P{O}_2$ is:

$3+x-4=0$

$x=+1$.

The oxidation state of $P$ atom in pyrophosphorus acid $H_4{P}_2{O}_5$ is:

$4+x-10=0$

$x=+3$.

The oxidation state of $P$ atom in orthophosphoric acid $H_{3}P{O}_4$ is:

$3+x-8=0$

$x=+5$.

Hence, option $B$ is correct.