Question

What is the oxidation number of the cetral metal in the complex $K_2\left[OsC{l}_{5}N\right]$?

Answer 1

Oxidation number of potassium $=+1$
Oxidation number of chlorine $=-1$
Oxidation number of N = -3
Let oxidation number of $Os=x$
$2(+1)+x+5(-1)+(-3)=0$
$2+x-5-3=0$
$2+x-8=0$
$x-6=0$
$x=+6$
Hence oxidation number of $Os$ in given complex is $+6$.