MHTCET 20 Apr 2026 Shift 2 Paper

Concept:A heteroleptic complex contains more than one type of ligand attached to the central metal ion.Explanation:Check each option for the number of different ligands present.Option A: Pentacarbonyliron(0) is $\left[\mathrm{Fe}(\mathrm{CO})_5\right]$.Only $\mathrm{CO}$ ligands are present, so it is homoleptic.Option B: Triamminetrinitrocobalt(III) is $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_3\left(\mathrm{NO}_2\right)_3\right]$.It contains two different ligands: $\mathrm{NH}_3$ (ammine) and $\mathrm{NO}_2^-$ (nitro).Therefore, this complex is heteroleptic.Option C: Tetraamminecopper(II) ion is $\left[\mathrm{Cu}\left(\mathrm{NH}_3\right)_4\right]^{2+}$.Only $\mathrm{NH}_3$ ligands are present, so it is homoleptic.Option D: Tetracyanonickelate(II) ion is $\left[\mathrm{Ni}(\mathrm{CN})_4\right]^{2-}$.Only $\mathrm{CN}^-$ ligands are present, so it is homoleptic.Answer:The heteroleptic complex is Option B: Triamminetrinitrocobalt(III).