Question

The fluorides BF3, AlFz, SiF4, and PFs are Lewis acids. The all form very stable fluoroanions when treated with lithium fluoride. In contrast, the three fluorides CF4, NF3, and SF do not react with lithium fluoride. Explain by selecting all that apply. O CFA and NF, have no available orbitals on the inner atoms to form additional bonds. BF3, AlF3, SiF4, and PFs all contain electron deficient inner atoms. BF3, AlF3, SiF4, and PFs all have the ability to form a new bond. CF4 and NF3 are also Lewis acids. In SF, the inner atom is sterically crowded, preventing another F" from approaching the Satom.

Answer 1

Correct statements are- 1, 3, 5 options

1. NF​​​​​3 and CH​​​​​4 , has no additional orbital to make new bonds.
2. Boron family, carbon family and nitrogen family are eletron deficient, electron precise and electron rich respectively.
3. All can form extra bond due to availability of the empty orbitals p or d- orbital.
4. Lewis acid are those which accept electron pair. CF​​​4 and NF3 both do not have empty orbital to accept electron pair so they are not Lewis acid.
5. In SF​​​6 , S is surrounded by 6 F-atoms which cause greater steric crowding due to this it do not form extra bond. Charge density is also high.

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