In H3PO3, basicity of the oxy acid is two. — p Block Elements Chemistry Question

💡 Solution & Explanation

Step 1: According to Fajans' rules, covalent character in ionic compounds increases with the size of the anion due to increased polarizability of the larger anion. Step 2: The size of the halide anions increases in the order: F- < Cl- < Br- < I-. This means polarizability increases, thereby increasing covalent character and decreasing ionic character from fluoride to iodide. Step 3: Thus, the decreasing order of ionic character is PbF2 > PbCl2 > PbBr2 > PbI2, matching option (a).