Question

The pair having the same magnetic moment is:
[At. No.: $Cr=24,Mn=25,Fe=26,Co=27]$

• A. $\left[Cr\right(H_{2}O{)}_6{]}^{2+}$ and $\left[Fe\right(H_{2}O{)}_6{]}^{2+}$
• B. $\left[Mn\right(H_{2}O{)}_6{]}^{2+}$ and $\left[Cr\right(H_{2}O{)}_6{]}^{2+}$
• C. $[CoC{l}_4{]}^{2-}$ and $\left[Fe\right(H_{2}O{)}_6{]}^{2+}$
• D. $\left[Cr\right(H_{2}O{)}_6{]}^{2+}$ and $[CoC{l}_4{]}^{2-}$

Answer 1

The correct option is A $\left[Cr\right(H_{2}O{)}_6{]}^{2+}$ and $\left[Fe\right(H_{2}O{)}_6{]}^{2+}$

$C{r}^{2+}\to d^4\to$ No of unpaired electron 4

$F{e}^{2+}\to d^6\to$ No of unpaired electron 4

Both configurations have 4 unpaired electrons as the ligands that they are bonded to, are weak field ligands.