Question

$Cr{O}_5$ has structure as shown, The oxidation number of chromium in the compound is?

• A. $+4$
• B. $+5$
• C. $+6$
• D. $+10$
• E. $0$

Answer 1

The correct option is C $+6$

By looking the above structure we can observe that 4 oxygen atoms are linked by peroxide linkage. So there oxidation state is -1 as in peroxide.

One oxygen atom is attached normally so its oxidation state is -2.

So oxidation state of $Cr$ is $x+4(-1)+(-2)=0,x=+6$