Between `NF_(3)` and `BF_(3), NF_(3)` is polar but `BF_(3)` is non-polar. In the `BF_(3)` molecule there is no lone pair of electrons on the central atom. The shape of this molecule is trigonal planar that is symmetrical. `NF_(3)` has three bond pairs and one lone pair. But due to the presence of a lone pair on nitrogen the polarities are not cancelled. Hence, the `NF_(3)` molecule is polar.
