What type of isomerism is exhibited by nitropentaamminechromium $(III)$ chloride?

Among $(i) [Co(NH_3)_6]Cl_3$,$(ii) [Ni(NH_3)_6]Cl_2$,$(iii) [Cr(H_2O)_6]Cl_3$,$(iv) [Fe(H_2O)_6]Cl_2$,the complex which is diamagnetic is $....$

$[Co(NH_3)_5SO_4]Br$ and $[Co(NH_3)_5Br]SO_4$ are a pair of which isomers?

Which of the following pairs of compounds has the same number of unpaired electrons?

The magnetic moments of the following,arranged in decreasing order,will be:-
$(i)$ $Co^{3+}$ (Octahedral complex with a strong field ligand)
$(ii)$ $Co^{3+}$ (Octahedral complex with a weak field ligand like $F^{-}$)
$(iii)$ $Co^{2+}$ (Tetrahedral complex)
$(iv)$ $Co^{2+}$ (Square planar complex)

Total number of geometrical isomers possible for the complexes $[NiCl_4]^{2-}$,$[CoCl_2(NH_3)_4]^{+}$,$[Co(NH_3)_3(NO_2)_3]$ and $[Co(NH_3)_5Cl]^{2+}$ is