Not every molecule with polar bonds is polar. Explain this statement. Use CCl©þ as an example.
3 answers
CCl(subscript 4) *
A molecule must satisfy two criteria to be polar.
a)it must have polar bonds.
b)it must NOT be symmetrical in three dimensions.
CCl4 has C-Cl bonds that differ in electronegativity; therefore, each of the C-Cl bonds is polar.
However, the CCl4 molecule, as a whole, is symmetrical (tetrahedral); therefore, the individual polar bonds are canceled and the molecule as a whole is not polar. Contrast this with CHCl3. The H on one C-H bond doesn't cancel the three C-Cl bonds at the other angles so it WILL be polar as a molecule. Look at CO2, a simpler molecule because it is linear. But since it is O=C=O, the molecule is symmetrical, the individual C-O polarities cancel, and the CO2 molecule is not polar. But HCN is polar because the C-H polarity is not th same as the C-N polarity. I may be able to find something on the web that shows pictures if you still don't quite understand.
a)it must have polar bonds.
b)it must NOT be symmetrical in three dimensions.
CCl4 has C-Cl bonds that differ in electronegativity; therefore, each of the C-Cl bonds is polar.
However, the CCl4 molecule, as a whole, is symmetrical (tetrahedral); therefore, the individual polar bonds are canceled and the molecule as a whole is not polar. Contrast this with CHCl3. The H on one C-H bond doesn't cancel the three C-Cl bonds at the other angles so it WILL be polar as a molecule. Look at CO2, a simpler molecule because it is linear. But since it is O=C=O, the molecule is symmetrical, the individual C-O polarities cancel, and the CO2 molecule is not polar. But HCN is polar because the C-H polarity is not th same as the C-N polarity. I may be able to find something on the web that shows pictures if you still don't quite understand.
mhv
1 answer