Question

What will be the average oxidation state of $P$ in $K_4{P}_2{O}_7$?

• A. $+4$
• B. $+5$
• C. $+2$
• D. $-3$

Answer 1

The correct option is B $+5$

$K_4\underset{--}{P_2}{O}_7$
charge on $K=+1$
charge on $O=-2$
Let $x$ be oxidation state of P
$2x+4-2\times 7=0$
$2x=10$
$x=+5$