B. E. Douglas, D. H. McDaniel, J. J. Alexander, Concepts and Models of Inorganic Chemistry, 3rd edition, John Wiley & Sons, New York, 1994, page 104.
 
 

Problem 2.32
 

Why is (CH3)2O quite soluble in H2O , and why is C2H6 very insoluble in H2O?
 
 
 

Answer:

Solubility requires an attractive interaction between the solute and the solvent. In the case of the water/ether mixture, both molecules are polar, allowing a dipole-dipole interaction, and the water can act as a hydrogen bond donor to the ether O atom, leading to a quite strong attraction. In the case of ethane/water, the only weak attraction possible between the two molecules is the van der Waal's interaction; since both molecules are small, this attraction is weak leading to little solubility of ethane in water.