Final answer:
The solubility difference between CH4 and CH3Cl in water can be explained by their molecular polarity. CH4 is nonpolar and exhibits weak interactions with water, leading to poor solubility, while CH3Cl is polar and forms stronger dipole-dipole interactions with water, hence it is more soluble.
Step-by-step explanation:
The difference in solubility of CH4 and CH3Cl in water can be attributed to their molecular structures and the types of intermolecular forces they can form with water. CH4 (methane) is a nonpolar molecule with symmetrical distribution of its hydrogen atoms around the central carbon atom. Because of this symmetry, methane does not have a permanent dipole moment and can only engage in weak London dispersion forces with water molecules, resulting in poor solubility.
CH3Cl (chloromethane), on the other hand, is a polar molecule due to the presence of the electronegative chlorine atom, which creates a permanent dipole. This allows chloromethane to engage in dipole-dipole interactions with water molecules, making it more soluble than methane. As a general rule, polar substances tend to dissolve in polar solvents such as water, while nonpolar substances are more soluble in nonpolar solvents.