Chemical Bonding And Molecular Structure Question 494
Question: Amongst the following, the total number of species which does/do not exist is : $ SF_6,BF_6^{3-},SF_4,OF_4,AlF_6^{3-},PH_5,PCl_5,NCl_5,SCl_6 $
Options:
A) 9
B) 5
C) 6
D) 8
Show Answer
Answer:
Correct Answer: B
Solution:
- [a] Amongst hexahalides of sulphur, only $ SF_6 $ is exceptionally stable for steric reason. In $ SCl_6, $ smaller S cannot accommodate six larger $ C{l^{-}} $ ions.
[b] $ PH_5 $ does not exist as there is large difference in the energies of s, p and d orbital’s of P and hence it does not undergo $ sp^{3}d $ hybridization.
[c] $ NCl_5 $ does not exist as there is no d-orbtial with N.
[d] $ BF_6^{3-} $ does not exist as there is no vacant d-orbital in B and hence it cannot exceed its covalency beyond four.
(e) Oxygen cannot exceed its covalency as it does not have d-orbital.
