_____ are insoluble in water but soluble in organic solvents.
Lipids
Lipid molecules are insoluble or sparingly soluble in water, but are readily soluble in organic solvents like ether, alcohol and benzene. Insolubility of lipids in water is due to the fact that the polar groups they contain are much smaller than their nonpolar portions.
The nonpolar chains are long complex hydrophobic hydrocarbon chains. If shaken in water, lipids often form small droplets or micelles. The complex thus formed, is called an emulsion. These non-polar complexes give them water repellent or hydrophobic properties.