[CSG]

Why does the solubility of alcohols and acids decrease as they get bigger? Surely as they get bigger, there will be more hydrogen available to hydrogen bond with?

[Smrt guy]

Hydrogen bond donors are only H atoms attached to electron withdrawing substituents (e.g. O, N).  The extra protons on the carbons do not participate in H-bonding (put oil in water and see how it interacts with the water).  Adding extra carbons makes the molecule more lipophilic ("fat loving" or oil-like).