In CrO5 the structure has one Cr=O and two peroxo (O2^2-) groups, so four O atoms are -1 and one is -2. What is the oxidation number of Cr?

JEE Main levelSingle correct optionDifficulty 2 of 3bn136

In $CrO X_{5}$ the structure has one Cr=O and two peroxo ( $O X_{2} X^{2 -}$ ) groups, so four O atoms are $- 1$ and one is $- 2$ . What is the oxidation number of Cr?

x + 4 (- 1) + 1 (- 2) = 0

gives

x = + 6

. Treating all five O as

- 2

would wrongly give

+ 10