Spin only magnetic moment of $[MnBr_{6}]^{4-}$ is $..... \ B.M.$ (round off to the closest integer)

Among the complex ions,$[Co(en)_2Cl_2]^{+}$,$[CrCl_2(C_2O_4)_2]^{3-}$,$[Fe(H_2O)_4(OH)_2]^{+}$,$[Fe(NH_3)_2(CN)_4]^{-}$,$[Co(en)_2(NH_3)Cl]^{2+}$ and $[Co(NH_3)_4(H_2O)Cl]^{2+}$,the number of complex ion$(s)$ that show$(s)$ cis-trans isomerism is

The number of possible optical isomers for $[Co(en)_2 Cl_2]^+$ is ....

The magnetic moment of $K_3[FeF_6]$ is ..... $B.M.$

The metal atom present in the complex $MABXL$ (where $A, B, X$ and $L$ are unidentate ligands and $M$ is metal) involves $sp^3$ hybridization. The number of geometrical isomers exhibited by the complex is:

The number of possible isomers of an octahedral complex $[Co(C_2O_4)_2(NH_3)_2]^-$ is