Why is water a poor solvent for organic molecules? Few organic molecules dissolve in water but why is this the case?
Pure water can form two hydrogen bonds per molecule.  The enthalpy of these hydrogen bonds is about 23 kJ/mol of water.  You have to give water a very good reason to rip apart its hydrogen bond network, and the interactions water experiences with the organic compounds often aren't enough, even considering increased entropy, to make this favorable.