Which type of isomerism is exhibited by the complexes $[Co(NH_3)_5SO_4]Br$ and $[Co(NH_3)_5Br]SO_4$?

Among the following ions,which one has the highest paramagnetism?

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)

Which of the following complex species is not expected to exhibit optical isomerism?

Which of the following ion/ions is/are diamagnetic?

Which of the following exhibits optical isomerism?