Analyze the bonds of ccl4. what is the shape of the ccl4 molecule? is it symmetrical? does this mean that the ccl4 molecule is polar or nonpolar?

C-Cl bond is polar.

As Cl is more electronegative than C,  

Cl pulls the shared electrons towards its side making the C-Cl bond polar.

Polar meaning C gets a partial positive charge and Cl gets a partial negative charge. Thus C-Cl bond becomes polar.

CCl4 molecule is tetrahedral.

And its shape is symmetrical.

That means its similar on all corners or all planes and it can be cut into equal halves from any plane.

C-Cl bond is polar.But the C-Cl polairty gets cancelled out as its pulled equally from all sides.

Since the molecule is symmetrical CCl4 is non polar.  

the answer is b. dilution