Which of the molecules below would have intermolecular dipole-dipole attractions?

Question

-CH3 -O- CH3

-H2

-CO2

-C Cl4

-Ca Cl2

Answer 1

Dipole-Dipole means polar!

So, we know its not H2

We know its not CCl4,

CaCl2 is polar.

C2O(H3)2 is not polar i believe. because the O has electrons around it.

and CO2 is polar.

Answer 2

For there to be dipole-dipole interaction there must be polar moleclues.

CH3OCH3 is not polar, hence not dipole-dipole interaction

H2 is not polar, ditto

CO2 is linear and not polar, ditto.

CCl4 is tetrahedral and not polar, ditto

CaCl2 is an ionic network solid, and not a polar moleclue

So it appears that none of these have dipole-dipole interactions.  All molecular compounds do exhibit London dispersion forces, though.