Which of the following ions has a magnetic moment of $5.93 \ BM$?

Which among the following is most paramagnetic?

The correct order of the spin only magnetic moment of metal ions in the following low spin complexes,$[V(CN)_6]^{4-}$,$[Fe(CN)_6]^{4-}$,$[Ru(NH_3)_6]^{3+}$,and $[Cr(NH_3)_6]^{2+}$,is

$A$ complex of a certain metal has a magnetic moment of $4.91 \ BM$,whereas another complex of the same metal with the same oxidation state has zero magnetic moment. The metal ion could be:

The existence of two different colored complexes of $[Co(NH_3)_4Cl_2]^+$ is due to which of the following?

$Cis-trans$ isomerism is exhibited by