NEET 2016 Physics and Chemistry Paper 2

1. $\mathrm{CO}_3^{2-}$ and $\mathrm{SO}_3^{2-}$ :- $\mathrm{CO}_3^{2-}$ : Carbonate ion has $4\mathrm{C}+3 \times 6\mathrm{O}+2$ (charge) $=24$ electrons.- $\mathrm{SO}_3^{2-}$ : Sulfite ion has $6\mathrm{S}+3 \times 6\mathrm{O}+2$ (charge) $=26$ electrons.- These ions are not isoelectronic.2. $\mathrm{ClO}_3^{-}$and $\mathrm{CO}_3^{2-}$ :- $\mathrm{ClO}_3^{-}$: Chlorate ion has $7\mathrm{Cl}+3 \times 6\mathrm{O}+1$ (charge) $=26$ electrons.- $\mathrm{CO}_3^{2-}$ : Carbonate ion has 24 electrons.- These ions are not isoelectronic.3. $\mathrm{SO}_3^{2-}$ and $\mathrm{NO}_3^{-}$:- $\mathrm{SO}_3^{2-}$ : Sulfite ion has 26 electrons.- $\mathrm{NO}_3^{-}$: Nitrate ion has $5\mathrm{N}+3 \times 6\mathrm{O}+1$ (charge) $=24$ electrons.- These ions are not isoelectronic.4. $\mathrm{ClO}_3^{-}$and $\mathrm{SO}_3^{2-}$ :- $\mathrm{ClO}_3^{-}$: Chlorate ion has 26 electrons.- $\mathrm{SO}_3^{2-}$ : Sulfite ion has 26 electrons.- These ions are isoelectronic.- Both ions have a trigonal pyramidal structure.- These ions are isostructural.Therefore, the correct pair is $\mathrm{ClO}_3^{-}$and $\mathrm{SO}_3^{2-}$.