MHTCET 11 Apr 2026 Shift 1 Paper

Concept:Central metal ion in a coordination compound behaves as an electron-pair acceptor.Explanation:A Lewis acid is any species that can accept a lone pair of electrons.In a complex compound, ligands donate lone pairs of electrons to the central metal ion.Thus, the ligand acts as a Lewis base and the central metal ion acts as a Lewis acid.Example: In $\left[\mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{4}\right]^{2+}$, $\mathrm{NH}_{3}$ donates lone pairs to $\mathrm{Cu}^{2+}$.So, $\mathrm{Cu}^{2+}$ is the Lewis acid.Answer:Option C: Lewis acid.