The type of isomerism shown by the complex $[CoCl_2(en)_2]$ is

Which of the following complexes has the maximum number of unpaired electrons?

The number of isomers possible for the complex $K_2[PtClBr_2(SCN)]$ is:

In which of the following orders are the given complex ions arranged correctly with respect to their decreasing spin-only magnetic moment?
$(i)$ $[FeF_{6}]^{3-}$
$(ii)$ $[Co(NH_{3})_{6}]^{3+}$
$(iii)$ $[NiCl_{4}]^{2-}$
$(iv)$ $[Cu(NH_{3})_{4}]^{2+}$

The magnetic moment of the complex $[Ni(NH_3)_6]Cl_2$ is

Identify the optically active compound from the following.