Hello, I need help solving this problem on intermolecular dispersion forces. Can you explain how I go about finding the answer?

Question

Which member of the following has the stronger intermolecular dispersion forces?
a. CO
CO2
neither of these

b. CH3CH2CH2CH2Br
CH3CH2CH2Br
neither of these

c. CH3Br
CH3Cl
neither of these

Answer 1

For CO2 vs CO, look at the structure. CO is a linear molecule (it must be because that is the only way to put two atoms together). Since the electronegativity of C is about 2.4 and that of O is about 3.5, the CO molecule is a dipole (it is a polar bond) because of the separation of charge. For the CO2 molecule; however, it is O=C=O and any dipole between the O=C on the left is canceled by the dipole between the C=O on the right; therefore, CO2 is not a polar molecule. It has a zero dipole moment. That is, CO molecules are polar and there is an attraction between polar molecules. CO2 is not polar and there is little attraction between molecules. Therefore, CO has the larger intermolecular force. For b, the same kind of reasoning except in this case one chain is longer than the other. So which molecule is the more polar? That will be the one with the larger intermolecular force. c is the same kind of thing but in this case compare the electronegativity of Br with that of Cl to get the more polar molecule. I hope this helps.

Answer 2

yea i got it

thanks!!!!!