MHTCET 16 May 2024 Shift 1 Paper

Concept:EAN (Effective Atomic Number) is calculated as: atomic number of the metal minus its oxidation state plus the total electrons donated by ligands.Explanation:In $\left[\mathrm{Zn}\left(\mathrm{NH}_{3}\right)_{4}\right]^{2+}$, zinc is present as $\mathrm{Zn}^{2+}$.Atomic number of zinc, $Z = 30$.Charge on the metal ion, $X = 2$ (oxidation state of $\mathrm{Zn}$).Each $\mathrm{NH}_{3}$ ligand donates one lone pair, i.e., 2 electrons.Number of ligands = 4, so total donated electrons, $Y = 4 \times 2 = 8$.Using the formula: $\text{EAN} = Z - X + Y$.So, $\text{EAN} = 30 - 2 + 8 = 36$.Answer:The EAN of Zn in $\left[\mathrm{Zn}\left(\mathrm{NH}_{3}\right)_{4}\right]^{2+}$ is $\mathbf{36}$, which matches option D.