Answer: First NH3 goes to any position; second NH3 goes cis to the first Cl- (Cl- labilises trans site, so second substitution is trans to Cl-).
- A First NH3 goes to any position; second NH3 goes cis to the first Cl- (Cl- labilises trans site, so second substitution is trans to Cl-)
- B Both ammonia ligands are said to substitute in a largely random, loosely controlled order overall in most cases under typical conditions
- C The second NH3 ligand is said to substitute specifically trans to the first NH3 ligand instead according to standard textbooks in general practice
- D Chloride is said to act generally as a passive spectator ion with little influence on the order as frequently described in most textbook accounts
Correct answer: A. First NH3 goes to any position; second NH3 goes cis to the first Cl- (Cl- labilises trans site, so second substitution is trans to Cl-)
Explanation: Step 1: [PtCl4]2- + NH3 → [Pt(NH3)Cl3]-. Step 2: Cl- trans to the NH3 is now trans-labilised; the second NH3 replaces this Cl-, giving the cis product.
The three common coordination geometries: octahedral (6 ligands), tetrahedral (4 ligands), and square planar (4 ligands in one plane).
Concept context
Study of compounds where a central metal atom is bonded to surrounding ligands. Covers nomenclature, types of isomerism, bonding theories (VBT, CFT), and applications in medicine, photography, and industry.