Question

Which of the five fluorine-containing molecules have no dipole moment?

Answer 1

The PCl3F2 and PF5 have no dipole moment. In PF5 the 5 polar bonds cancel out. In PCI3F2 the 3 CI atoms make a triangle and the angle between them is 120 and they cancel out. the 2 F atoms each go to a side of this triangle and make vertical line to the surface of Chlorines because F is more electronegative and smaller.