Final answer:
Both CH₃Cl and CH₂Cl₂ are polar molecules because they contain polar covalent bonds due to the electronegativity difference between chlorine atoms and carbon/hydrogen, and the molecules have an asymmetrical shape which leads to a net dipole moment.
Step-by-step explanation:
The question asks which of the following molecules is polar: CH₃Cl or CH₂Cl₂, or both. A molecule is polar if it has a net unequal distribution of electrons in its covalent bonds, resulting in a partial positive charge on one side and a partial negative charge on the other side, known as a dipole. The presence of chlorine atoms (Cl), which are more electronegative than carbon (C) and hydrogen (H), in both CH₃Cl and CH₂Cl₂ will create polar covalent bonds. In CH₃Cl, the single Cl atom creates an asymmetrical shape, leading to a net dipole moment. In CH₂Cl₂, the two Cl atoms are arranged tetrahedrally with respect to the carbon atom, which also creates an asymmetrical shape and a net dipole moment. Therefore, the correct answer is (c) both of them contain polar bonds and are polar molecules.