Question

Give the oxidation state of underlined.
$\underset{–}{Co}Se{O}_4$.

Answer 1

Oxidation number of $Se$ is +6 and of $O$ is -2.Total charge on compound is 0.

Let oxidation number of $Co$ is $x$

So $x+6+4(-2)=0$

$x=+2$

So oxidation number of $Co$ is +2.