Which of the given compound(s) can act as Lewis acid in both monomer and dimer form ? — p Block Elements Chemistry Question

💡 Solution & Explanation

Step 1: Examine reaction I: XeF6 acts as a Lewis acid to accept a fluoride ion from NaF, forming Na+[XeF7]^- (feasible). Step 2: Examine reaction II: In the solid state, phosphorus pentachloride (PCl5) auto-ionizes into tetrahedral [PCl4]+ and octahedral [PCl6]- ions (feasible). Examine reaction III: The hexaaquaaluminium cation [Al(H2O)6]3+ is acidic and undergoes hydrolysis in water to produce [Al(H2O)5OH]2+ and hydronium (feasible). Step 3: Since all three transformations (I, II, and III) are chemically possible, option (a) is the correct choice.