Question

The oxidation state of cobalt in the complex compound
$\left[Co\right(N{H}_3{)}_6]C{l}_3$ is

• A. $+3$
• B. $+6$
• C. $+5$
• D. $+2$

Answer 1

The correct option is A $+3$

Balance the charge of the complex.

The charge of $S{O}_4=-2$.

The charge of $H_{2}O=0$ (neutral ligand).

The charge of $NO=+1$.

So, we have $x+1+5\left(0\right)=2$, where $x$ is the charge of iron in the complex.

$\therefore x=1$.

Hence option A is correct.