Why are most organic compounds insoluble in water?

Answer 1

Water molecules are attracted to each other with some very strong forces, like hydrogen bonding and dipole-dipole attractions. Those attractions lower the energy of the water molecules and make their interactions very favorable (which is why water has such a high melting and boiling point). To dissolve an organic molecule (or any molecule for that matter) into water, you need to physically separate these water molecules from each other to carve out space for the molecules to reside. This means breaking up some of these really favorable hydrogen bonding and dipole-dipole interactions. The only way this is going to happen is if the interactions the water molecules have with the organic molecules are as good if not better than the interactions the water molecules were having with each other. Those organic molecules that can form hydrogen bonds and/or are polar tend to be soluble in water because they can replace the nice interactions between the water molecules. Those organic molecules that are non-polar or are really big and partially non-polar will not be able to replace the happy water-water interactions and so will be excluded (i.e. sit in a layer on top of the water). Ironically, from an energy standpoint, the organic molecules would love to hang out with the water molecules and benefit from their strong dipoles, but just like nerds at a party full of "cool kids" are excluded from those interactions because they cannot reciprocate with a strong dipole of their own.

Answer 2

The solubility of a substance in water depends on whether its molecules are polar. Polar substances will dissolve more readily in water (which is a polar substance itself) than nonpolar substances will.

Answer 3

Many organic compounds, such as ethanol and lactic acid, are actually fully soluble in water.

But many others are not as they contain nonpolar hydrocarbon chains and nonpolar substances are generally insoluble in polar substances such as water.

Answer 4

Organic compounds are typically nonpolar or have limited polarity, which makes them unable to form strong interactions with water molecules. This leads to poor solubility in water, as water is highly polar and tends to only dissolve other polar or ionic substances. Additionally, the presence of hydrophobic groups in organic compounds further reduces their ability to dissolve in water.

Answer 5

ionic compounds are polar,only a polar solvent can dissole a polar compound,so salt will not dissolve in oil but will dissolve in water because water is polar.....

Answer 6

Most organic compounds have nonpolar molecules.