JEE Advanced 2021 · Paper 1, Chemistry question 19

Geometrical isomers. The cation $\ce{[Pt(NH3)4Cl2]^{2+}}$ is octahedral $\ce{MA4B2}$, so it has cis and trans forms.

Ionisation isomers. Exchanging ligands with the counter-ions gives:

• $\ce{[Pt(NH3)4Cl2]Br2}$ (cis, trans);
• $\ce{[Pt(NH3)4Br2]Cl2}$ (cis, trans);
• $\ce{[Pt(NH3)4ClBr]ClBr}$ (cis, trans).

Total: $3\times2=6$.