Question: The pair of metal ions that can give a spinonly magnetic moment of $3.9 \mathrm{BM}$ for the complex $\left[\mathrm{M}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right] \mathrm{Cl}_{2}$, is :
$\mathrm{Cr}^{2+}$ and $\mathrm{Mn}^{2+}$
$\mathrm{V}^{2+}$ and $\mathrm{Co}^{2+}$
$\mathrm{V}^{2+}$ and $\mathrm{Fe}^{2+}$
$\mathrm{Co}^{2+}$ and $\mathrm{Fe}^{2+}$
Correct Option: , 2
Solution:
