A Colligative Property Experiment using the Solvent Paraffin Wax

In this educational lab project, we propose using paraffin wax as an alternative organic solvent to those used in academic labs to demonstrate the concept of freezing point depression. We opted to use paraffin wax pellets as an organic solvent because many schools worldwide do not have the resources and access to purchase specialty chemicals. Paraffin wax is readily available to schools, safe to use, non-toxic, does not release a pungent or irritating smell, and yields reproducible results and trends. Data was gathered from at least fifty Chemistry Lab reports and assessed statistically against data obtained under controlled conditions. The Freezing point depression constant Kf (i.e. freezing point constant) of commercial paraffin wax is not available in the literature and our experimental analysis yielded a reproducible range of Kf = 5.0 to 5.5 oC.kg/mol at a melting point of 54 oC. We picked Benzophenone and Naphthalene (i.e. mothballs) as two compatible nonpolar solutes that worked well with the solvent paraffin wax.