CH2Cl2 vs C6H4Cl2

[Talia Dini - 3I]

Why is CH2Cl2 polar but C6H4Cl2 is nonpolar?

[Jordi M 2I]

CH2Cl2 is a polar molecule because of its tetrahedral shape. No mater where you place the chlorine atoms, there will be a net dipole moment. C6H4Cl2 on the other hand is a cyclic structure meaning it forms a ring. In this structure, the chlorines are position are opposing ends which would cancel their dipole moments. It is possible for this structure to be polar if the arrangement of chlorine atoms were changed.

[LarisaAssadourian2K]

I agree with the previous post. The polarity of CH2Cl2 is because of its shape and the positioning of the chlorine atoms, which causes a dipole moment.

[Marcus Lagman 2A]

Hello!

This post above really explains when a molecule is polar or nonpolar. And because of this, I say the best way to determine a molecule is polar or nonpolar is to look at the geometry. If the molecule's atoms not symmetrical, this means that there are partial charges that are creating a dipole moment pointing to a favored direction. These dipole moments determine whether a molecule is polar or nonpolar! In addition, do be careful with dipole moments. Sometimes they may seem to cancel each other out, such as the case in CH2Cl2 but because of its tetrahedral shape, the molecule's dipole moments would point in the direction between the chlorine atoms.

I hope this helps!