question_answer

The hybridisation and magnetic moment of complex \[[Cr{{({{H}_{2}}O)}_{6}}]\,C{{l}_{2}}\] is

A) \[s{{p}^{3}}{{d}^{2}},4.89\,BM\]

B) \[{{d}^{2}}s{{p}^{3}},4.89\,BM\]

C) \[ds{{p}^{2}},5.89\,BM\]

D) \[s{{p}^{3}}{{d}^{2}},3.39\,BM\]

Correct Answer: A

Solution :

\[Cr\]is in \[+2\] oxidation state in\[[Cr{{({{H}_{2}}O)}_{6}}C{{l}_{2}}\]. The electronic configuration of

\[C{{r}^{2+}}\] is \[3{{d}^{4}}4{{s}^{0}}\]

As \[{{H}_{2}}O\]is a weak field ligand, so pairing will not occur.

Thus, the hybridisation of \[{{\left[ Cr\left( {{H}_{2}}O \right)6 \right]}^{2+}}\] \[s{{p}^{3}}{{d}^{2}}\]

Magnetic moment \[=\sqrt{n\left( n+2 \right)}\]

For this complex, \[n=4\]

\[\mu =\sqrt{4\left( 4+2 \right)}\]

\[=\sqrt{24}\]

\[=4.89BM\]