Question

Calculate the oxidation number of phosphorus in $HP{O}_3^{2-}$.

Answer 1

Let the oxidation number of phosphorus is $x$.

$HP{O}_3^{2-}$

$+1+x+(-2)\times 3=-2$

$+1+x-6=-2$

$x-5=-2$

$x=-2+5$

$X=+3$

Thus, O.S. of phosphorous is +3