H2O→H3O+
NH3→NH4+
BF3→BF4-
CH4→C2H6
(A) Both CH4 and C2H6 have sp3 hybridization and tetrahedral shape
(B) Both NH3 and NH4+ have sp3 hybridization. But the shape of NH3 is pyramidal and shape of NH4+ is tetrahedral
(C) Both H2O and H3O+ have sp3 hybridization. H2O is bent shaped molecule and H3O+ is pyramidal
(D) BF3 → BF4- involves change in both shape and hybridization. BF3 is trigonal planar with sp2 hybridization. BF4- is tetrahedral with sp3 hybridization. Hence, option D is correct.