Question

Oxidation state of nitrogen in $\left[Co\right(N{H}_3{)}_{5}Cl]C{l}_2$ is $-x$. The value of $x$ is :

Answer 1

Let $x$ be the
oxidation state of $N$ in $\left[Co\right(N{H}_3{)}_{5}Cl]C{l}_2$.
Since the
overall charge on the complex is $0$, the sum of oxidation states of all
elements in it should be equal to $0$.
Therefore, consider the $N{H}_3$ ligand,
$x+3=0$ or, $x=-3$
Hence, the oxidation of $N=-3$.