Chemistry - Coordination Chemistry Question with Solution | TestHub

Question Explanation: Count paramagnetic complexes with at least two unpaired electrons.

Concept: Magnetic Properties of Coordination Compounds

Solution: Paramagnetism depends on the number of unpaired electrons (n), determined by metal oxidation state and ligand field strength.

${\left[{\mathrm{MnCl}}_4\right]}^{2-}:{\mathrm{d}}^5$, weak field $\to \mathrm{n}=5$

$\left[{\mathrm{Mn}}_2(\mathrm{CO}{)}_{10}\right]:\mathrm{n}=0$ (diamagnetic)

${\left[\mathrm{V}(\mathrm{CO}{)}_6\right]}^{-}:{\mathrm{d}}^6$, strong field $\to \mathrm{n}=0$

$\left[\mathrm{Ni}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6\right]{\mathrm{Cl}}_2:{\mathrm{d}}^8$, weak field $\to \mathrm{n}=2$

$\left[\mathrm{Pt}{\left({\mathrm{NH}}_3\right)}_2{\mathrm{Cl}}_2\right]:{\mathrm{d}}^8,5\mathrm{d}$ metal $\to \mathrm{n}=0$

${\left[\mathrm{Co}{\left({\mathrm{H}}_2\mathrm{O}\right)}_4\right]}^{2+}:{\mathrm{d}}^7$, weak field $\to \mathrm{n}=3$

${\mathrm{K}}_3\left[\mathrm{Cr}(\mathrm{CN}{)}_6\right]:{\mathrm{d}}^3$, always $\to \mathrm{n}=3$ Count $(\mathrm{n}\ge 2)=4$

Final Answer: 4