Question

The oxidation number of the metal in $\left[Co\right(CN\left)\right(H_{2}O\left)\right(en{)}_2{]}^{2+}$ is:

• A. 3
• B. 2
• C. 1
• D. -3

Answer 1

The correct option is A 3

$\left[Co\right(CN\left)\right(H_{2}O\left)\right(en{)}_2{]}^{2+}$

As we know,
Charge on :

$C{N}^{-}=-1$

$H_{2}O=0$

$(en{)}_2=0$

So, to find the oxidation state of metal

$\to$ $x-1+0+0=+2$

$x=+3$.