4.25 a

[Noah Carey 1G]

This problem asks to predict whether CH2Cl2 is polar or nonpolar. Can't the dipole moments of CH2Cl2 cancel out when H is across from H and Cl is across from Cl? Why do you assume H is across from Cl?

[kendallbottrell]

When you're doing polar/nonpolar problems, it is important to think of the 3D model/shape because you could see that no matter where you put the H or Cl, dipole moments will not cancel each other. If you only look at the Lewis structure, then you can get confused because it would look like they would cancel. In this case, the shape would be a tetrahedral, so there is no way that the moments would be opposite of each other and therefore cancel.

[Nicole Shak 1L]

Since the shape is a tetrahedral (3D shaped), the charges do not cancel out. It's polar since Cl has a stronger pull on electrons than the H atoms.