Question

The oxidation number of phosphorus in $P{O}_4^{3-},P_4{O}_{10}$ and $P_2{O}_7^{4-}$ is?

• A. $+5$
• B. $+3$
• C. $-3$
• D. $+2$

Answer 1

Answer: (A)

$+5$

Oxidation number of oxygen in these compounds is -2. So we can find oxidation number of phosphorus.

In ${PO}_4^{3-}$,$x+4(-2)=-3,x=+5$

In $P_4{O}_{10}$,$4\left(x\right)+10(-2)=0,x=+5$

In ${P_{2}O}_7^{-2}$,$2\left(x\right)+7(-2)=-4,x=+5$