Which of the following isomerism is not possible for complexes having molecular formulas:
$(i) \ Pt(SCN)_2 \cdot 3PEt_3$
$(ii) \ CoBr \cdot SO_4 \cdot 5NH_3$
$(iii) \ FeCl_3 \cdot 6H_2O$

Given below are two statements:
Statement $I$: $A$ solution of $[Ni(H_2O)_6]^{2+}$ is green in colour.
Statement $II$: $A$ solution of $[Ni(CN)_4]^{2-}$ is colourless.
In the light of the above statements,choose the most appropriate answer from the options given below:

Which of the following complexes does not show optical isomerism?

If $n$ is the number of unpaired electrons,then the magnetic moment $(B.M.)$ of a transition metal/ion is given by:

The diamagnetic species is

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