Statement I: Only \([Pt(NH_3)_2]Cl_2\) reacts with oxalic acid \((H_2C_2O_4)\) to form \([PtCl_2(ox)^{2−}]\) not the trans isomer
Statement II: The oxalate ion is a bidentate ligand that occupies adjacent positions only
Answer & explanation
Correct answer: option 1
The answer is (1) Both Statement I and statement II are correct and statement II is the correct explanation of statement I.
Statement I is correct because the oxalate ion is a bidentate ligand, which means that it can bind to the metal ion at two different positions. In the case of \([Pt(NH_3)_2]Cl_2\), the oxalate ion can bind to the metal ion in either the cis or trans position. However, the cis isomer is more stable than the trans isomer, so it is the only isomer that is formed.
Statement II is also correct because the oxalate ion is a bidentate ligand, which means that it can only bind to the metal ion in adjacent positions. This is because the two oxygen atoms of the oxalate ion need to be in close proximity to each other in order to form a bond with the metal ion.
The reason why only the cis isomer of \([PtCl_2(ox)^{2−}]\) is formed is because it is more stable than the trans isomer. The stability of the isomers is due to the steric interactions between the chloride ions and the oxalate ions. In the cis isomer, the chloride ions are further apart, which minimizes the steric interactions. In the trans isomer, the chloride ions are closer together, which increases the steric interactions.