AIIMS 2019 Chemistry Molecular Geometry MCQ Question

Option A is correct because the structure of BO₃³⁻ (borate ion) features a trigonal planar geometry with a central boron atom bonded to three oxygen atoms, each with a formal charge of -1, resulting in an overall charge of -3. In contrast, SO₃²⁻ (sulfite ion) has a tetrahedral arrangement around the sulfur atom, with one of the oxygen atoms bearing a double bond and the other two single-bonded with a -1 charge each, leading to a total charge of -2. The distinct geometries and bonding characteristics of these polyatomic ions highlight the differences in their electron configurations and resonance structures.