Modern Student laboratory: Spactroscopy Using Infrared Spectroscopy Measurements To Study Intermolecular Hydrogen Bonding Calculating the Degree of Association, Equilibrium Constant, and Bond Energy for Hydrogen Bonding in Benzyl Alcohol and Phenol H. Frohlich LCAM, b&t.351, Universite Paris- XI, F-91405 Orsay Cedex, France The notion of hydrogen bonding has been known since the early 1920's fmm work done in the laboratory of G. N. Lewis (13). This Journal has previously reviewed the large amount of literature that accounts for the various aspects of this type of bond (4). Phenomena Associated with Hydrogen Bonding In the condensed phase, molecules that contain certain functional groups (e.g., a hydroxyl group) can associate with one another by an intermolecular hydrogen bond. Well-known examples of compounds with such weak bonds are water and oxalic acid. Hydrogen bonds are responsible for many interesting physical phenomena, such as the surprisingly high boiling andmelting points ofwater, compared with those ofhydrogen sulfide. Also, hydrogen bonding explains why oxalic acid crystallizes in two distinct structures, u and P, depending on the way in which the molecnles are linked (5). In spite of its low binding energy, the great importance of the hydrogen bond stems from its presence in molecules of biological interest. Typical results of the action of hydrogen bonds include the double-helix structure of DNA and the low water miscibility of bilirubin, a hemoglobin degradation product (6). The Laboratory Project Unfortunately, student laboratory experiments in this field are rather u m m m o n (7). This paper will present a simple IR spectroscopy experiment tl$
