Cisplatin, cis-[Pt(NH3)2Cl2]\text{cis-}[\text{Pt}(\text{NH}_3)_2\text{Cl}_2]cis-[Pt(NH3)2Cl2], is a square planar transition metal complex used as an anti-cancer drug. Inside the cell, where the concentration of chloride ions is low, cisplatin undergoes an activation reaction before it binds to DNA.
Which of the following describes this activation reaction?
Replacement of one or both NH3\text{NH}_3NH3 ligands by water molecules
Replacement of one or both Cl−\text{Cl}^-Cl− ligands by water molecules
Oxidation of Pt(II)\text{Pt(II)}Pt(II) to Pt(IV)\text{Pt(IV)}Pt(IV)
Isomerisation of the cis-isomer to the trans-isomer
