Question

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

• A. Phosphonic acid $(H_3PO_3)$
• B. Phosphinic acid $(H_3PO_2)$
• C. Pyrophosphorus acid $(H_4P_2O_5)$
• D. Orthophosphoric acid $(H_3PO_4)$

Answer 1

Answer: (B)

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 $
$x=+5$