Why is #BF_3# considered to be a non-polar molecule, any yet #B-F# bonds are polar?

1 Answer
Aug 11, 2016

Answer:

Molecular polarity results from the #"vector sum"# of the individual bond dipoles.

Explanation:

We know (i) the the #B-F# bond is polar; and (ii) that the #/_F-B-F# bond angles are #120""^@#. When the individual bond dipoles are summed in a vector fashion, the resultant is necessarily #0#. Thus boron trifluoride is non-polar. Capisce?