Question

What is the oxidation state of the underlined atoms in $\left[\underset{–}{Cr}\right(CN{)}_6{]}^{3-}$?
(answer is modulus of oxidation state)

Answer 1

Let the oxidation state of $Cr$ in $\left[\underset{–}{Cr}\right(CN{)}_6{]}^{3-}$ be $x$.
$x+6(-1))=-3$
$x=+3$
Hence, the oxidation state of $Cr$ in $\left[\underset{–}{Cr}\right(CN{)}_6{]}^{3-}$ is $+3$.