Question

Find the number of unpaired electron in axial d-orbitals of X?

• A. 0
• B. 1
• C. 2
• D. 3

Answer 1

The correct option is A 0

When a mixture containing chloride ion is heated with $K_{2}C{r}_2{O}_7$ and concentrated $H_{2}S{O}_4$, deep orange-red fumes of chromyl chloride $\left(Cr{O}_{2}C{l}_2\right)$ are formed.

$K_{2}C{r}_2{O}_7+4NaCl+6H_{2}S{O}_4\to 2KHS{O}_4+4NaHS{O}_4+2Cr{O}_{2}C{l}_2\downarrow +3H_{2}O$

$\text{Orange-red fumes}$

So in this case, X is $Cr{O}_{2}C{l}_2$.

Oxidation state of $Cl=-1,O=-2,Cr=x$

$x+2\times (-2)+2\times (-1)=0\Rightarrow x=+6$

Oxidation State of $Cr=+6$

Electronic configuration of $C{r}^{+6}=\left[Ar\right]3d^{0}4s^0$

It has zero unpaired d-electron.

Option $A$ is correct.