Ex: CH3Cl is more polar than CHCl3
Hey Justin! So for CH3Cl, there is only one Cl pulling down on the C in the center because Cl is highly electronegative. The H's are not really pulling in the compound, so the Cl is going to create a huge dipole.
However, for the compound CHCl3, there are now 3 Cl's pulling each with equal force. This means that the electronegativity is equal among them and the dipole will balance out. This is why it is less polar-there is less of a dipole.
Hope this helps! Let us know if you have any other questions :)