When BCl ₃ undergoes hydrolysis in an alkaline aqueous medium, it forms a complex anion X . Separately, when AlCl ₃ is dissolved in an acidified aqueous solution, it forms a complex cation Y . The hybridization of the central atom in complex species X and Y , respectively, are:

Step-by-step solution

In an alkaline aqueous medium, BCl ₃ undergoes hydrolysis to form the tetrahydroxoborate(III) ion, [ B ( OH )₄]^- . Since boron lacks d-orbitals, it restricts its maximum covalency to 4. The hybridization of boron in [ B ( OH )₄]^- is sp ^3 . In an acidified aqueous solution, AlCl ₃ forms the hexaaquaaluminium(III) ion, [ Al ( H ₂ O )₆]³⁺ . Aluminium has vacant 3d-orbitals and can expand its coordination number to 6. The hybridization of aluminium in [ Al ( H ₂ O )₆]³⁺ is sp ^3 d ^2 . Answer: sp ^3 and sp ^3 d ^2