Freezing point depression is a colligative property that is directly related only to the number, but not the nature, of particles (ions and molecules) in solution. For the first time, the ionization constant of a carboxylic acid is determined in a non-traditional method that does not require the titration of the acid with a standardized base solution. This project involves the use of thermal probes to determine the ionization constant of a carboxylic acid using the experimentally obtained value of the van't Hoff factor of their aqueous solutions as long as the Ka value is above 10-3. The ionized portion of the solute is measured through a derived equation that corresponds to the freezing point depression temperature. The measured Ka values of various carboxylic acids were determined at various concentrations. The experiment is fast, uses extremely low concentrations of the solute, and the results are easily and infinitely reproducible, leaving very little waste.

Determination of the ionization constant of carboxylic acids using freezing point depression measurements

254th National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.