AIEEE 2004 Chemistry Solved Paper

Regular Tetrahedral structure is possible in sp3 hybridization where central atom has 4 bond pair and no lone pair.
(a) XeF4 is sp3d2 hybridised and structure is square planar.(b) [Ni(CN)4]−2 is coordinate compound and oxidation number of Ni is +2.
Electronic configuration of Ni+2 is =[Ar]3d8But because of CN−ion which is a strong field ligand, it can perform pairing of electron.And the structure of dsp2 hybridization is square planar.(C) BF4−,4 bond pair present so angle is 109∘28′ and sp3 hybridised. So structure is regular tetrahedral.(d) SF4 is sp3d hybridised and structure is see-saw.