The great similarity of the two molecules results in solutions where the water molecules and CH 3 CH 2 OH are interchangeable. There is no limit to the possible concentration of water in ethanol or ethanol in water. The molecules in solution are essentially interchangeable. Polar compounds dissolve in polar compounds and nonpolar dissolve in nonpolar. The types of intermolecular forces dictate these results.
Hexane has a six carbon chain and is nonpolar.
Dodecane has a 12 carbon chain and is nonpolar as well.