Question

Bf3 is a polar molecule but it does not show dipole moment why

Answer 1

Some molecules have polar bonds, but do not have a net dipole moment. The polarity of molecules depends on the polarity of the bonds and the geometry of the molecule. ... As a result, the bond moments of the C = O bonds cancel each other, and the molecule has no net dipole moment.

Answer 2

It has polar bonds but vector sum of their dipole moment is zero. Its structure is plane triangular and angle is 120°. Hence it is polar molecule.