Gasoline does not dissolve in water due to its chemical composition and the nature of its molecules. Gasoline is primarily made up of hydrocarbons, which are molecules consisting of hydrogen and carbon atoms. These hydrocarbons are nonpolar, meaning they do not have a significant charge difference across their molecules.
On the other hand, water is a polar molecule. This polarity arises because water has a partial positive charge on one side (the hydrogen atoms) and a partial negative charge on the other side (the oxygen atom). The polar nature of water allows it to effectively dissolve other polar substances through interactions like hydrogen bonding.
When a nonpolar substance like gasoline is introduced to water, the two molecules do not interact well. Instead of mixing, they separate: gasoline floats on top of water because it is less dense. This lack of interaction between nonpolar and polar substances explains why gasoline does not dissolve in water.