COMEDK 2025 Afternoon Solved Paper

Concept:Identify which complex’s IUPAC name does not match the structure.Explanation:Check each pair from the table.Pair A – P: $\left[\mathrm{CoBr}_2(\mathrm{en})_2\right] \mathrm{Cl}$ named “Dibromidodi‑(ethan‑1,2‑diamine)cobalt(III) chloride”. Correct.Pair B – Q: $\mathrm{Na}\left[\mathrm{PtBrCl}\left(\mathrm{NO}_2\right)\left(\mathrm{NH}_3\right)\right]$ named “Sodium amminebromidochloridonitrito‑N‑palatinate(II)”. Two errors:1. $\mathrm{NO}_2$ bonded through nitrogen is called “nitro”, not “nitrito‑N”.2. “Palatinate” is a misspelling; it should be “platinate”.Thus the name is incorrect.Pair C – R: $\left[\mathrm{Cr}\left(\mathrm{H}_2\mathrm{O}\right)_2\left(\mathrm{NH}_3\right)_4 \mathrm{Cl}\right] \mathrm{SO}_4$ named “Tetraamminediaquachloridochromium(III) sulphate”. Correct.Pair D – S: $\left[\mathrm{Pt}\left(\mathrm{NH}_3\right)_4\right]\left[\mathrm{PtCl}_4\right]$ named “Tetraammineplatinum(II) tetrachloridoplatinate(II)”. Correct.Only pair B – Q has a wrong name.Answer:B