GKFix MCQ Question

Which metal in the list exhibits a secondary valence of 6 in its compound with ammonia?

• A. Platinum in PtCl₂.2NH₃
• B. Palladium in PdCl₂.4NH₃
• C. Cobalt in CoCl₃.4NH₃
• D. Platinum in PtCl₄.2HCl