How many geometrical isomers will $[Pt(NH_3)(NH_2OH)(H_2O)(py)]^+$ form?

The complexes $[Co(NH_3)_6][Cr(C_2O_4)_3]$ and $[Cr(NH_3)_6][Co(C_2O_4)_3]$ exhibit which type of isomerism?

An octahedral complex having molecular composition $Co \cdot 5NH_3 \cdot Cl \cdot SO_4$ has two isomers $A$ and $B$. The solution of $A$ gives a white precipitate with $AgNO_3$ solution and the solution of $B$ gives a white precipitate with $BaCl_2$ solution. The type of isomerism exhibited by the complex is,

Which of the following planar complex is diamagnetic and shows stereo isomerism?

The correct order of spin-only magnetic moments among the following is: (Atomic number: $Mn = 25, Co = 27, Ni = 28, Zn = 30$)

The octahedral complex $[Co(NH_3)_5SO_4]Cl$ exists in two isomeric forms $X$ and $Y$. Isomer $X$ reacts with $AgNO_3$ to give a white precipitate,but does not react with $BaCl_2$. Isomer $Y$ gives a white precipitate with $BaCl_2$ but does not react with $AgNO_3$. Isomers $X$ and $Y$ are $.....$