The complex compounds $[Co(NH_3)_5 SO_4] Br$ and $[Co(NH_3)_5 Br] SO_4$ are

Which of the following compounds shows optical isomerism?

In a particular isomer of $[Co(NH_3)_4Cl_2]^0$,the $Cl-Co-Cl$ angle is $90^\circ$. This isomer is known as:

The number of paramagnetic metal complex species among $[Co(NH_3)_6]^{3+}$,$[Co(C_2O_4)_3]^{3-}$,$[MnCl_6]^{3-}$,$[Mn(CN)_6]^{3-}$,$[CoF_6]^{3-}$,$[Fe(CN)_6]^{3-}$ and $[FeF_6]^{3-}$ with the same number of unpaired electrons is $............$

In $[Cr(C_2O_4)_3]^{3-}$,the isomerism shown is :-

The complex that shows Facial - Meridional isomerism is