Answer:
Step-by-step explanation:
CH3Cl is polar while CCl4 is non polar.
When we consider whether something is polar or not we have to consider the following:
-Molecular symmetry
-Polar bonds (based on Electronegativity)
-Whether or not all the bonds are equal in magnitude
So for CCl4:
-All of the bonds are equal, in that all the electronegativity differences (delta EN) are the same.
-There are polar bonds as the delta EN between Cl (EN = 3.0) and C (EN=2.5) is 0.5 which means the bond is polar covalent
But when we look at the symmetry of the molecule (by drawing the lewis structure) there are no lone pairs, meaning that the molecule is symmetrical and therefore, it is non polar.
For CH3Cl:
-There are polar bonds here whether between C-H or C-Cl like above, both delta EN are greater than or equal to 0.5
-But, all of the bonds are not equal in strength. Cl (3.0) atoms have much higher electronegativity values than H (2.1) and there for they will "pull" the electrons closer and polarize the molecule. Therefore, the differences in bonds causes this molecule to be asymmetrical, and hence polar.
