COMEDK 2025 Morning Solved Paper

Concept:Count the valence electrons on the central atom, subtract electrons used in bonds, the remainder gives lone pairs.Explanation:For $\mathrm{SO}_2$ (A): S has 6 valence electrons, forms two double bonds (uses 4 electrons), remaining 2 electrons → 1 lone pair.For $\mathrm{ClF}_3$ (B): Cl has 7 valence electrons, forms three single bonds (uses 3 electrons), remaining 4 electrons → 2 lone pairs.For $\mathrm{BF}_3$ (C): B has 3 valence electrons, forms three single bonds (uses 3 electrons), remaining 0 electrons → 0 lone pairs.For $\mathrm{BrF}_5$ (D): Br has 7 valence electrons, forms five single bonds (uses 5 electrons), remaining 2 electrons → 1 lone pair.For $\mathrm{XeF}_4$ (E): Xe has 8 valence electrons, forms four single bonds (uses 4 electrons), remaining 4 electrons → 2 lone pairs.For $\mathrm{SF}_6$ (F): S has 6 valence electrons, forms six single bonds (uses 6 electrons), remaining 0 electrons → 0 lone pairs.Thus, (i) two lone pairs on central atom: B ($\mathrm{ClF}_3$) and E ($\mathrm{XeF}_4$).(ii) one lone pair on central atom: A ($\mathrm{SO}_2$) and D ($\mathrm{BrF}_5$).Answer:Option C: (i) B & E, (ii) A & D.