Chemical Bonding And Molecular Structure Ques 53

53. Which of the following would have a permanent dipole moment?

[2005]

(a) $SiF_4$

(c) $XeF_4$

(b) $SF_4$

(d) $BF_3$

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Answer:

Correct Answer: 53.(b)

Solution:

(b) $SF_4$ has permanent dipole moment. $SF_4$ has $s p^{3} d$ hybridization and see saw shape (irregular geometry).

$ \mu \neq 0 $

Whereas $XeF_4$ shows square planar geometry, $SiF_4$ has tetrahedral shape and $BF_3$ has Trigonal planar shape. All these are symmetric molecules. Hence $ _{\mu}=0$.