Sample B

Using Melting Point to Determine the Identity of an Unknown Organic Acid

Martha A. Hass
Albany College of Pharmacy, Organic Chemistry Lab
Tuesday Morning Section
June 15, 2002

The identity of an unknown organic acid was determined. The compound was taken from a list of twenty, known organic acids, each with different melting points. An experimental melting point was determined for the unknown compound using a Fisher-Johns melting point apparatus. The thermometer of the apparatus was calibrated using benzoic acid as a standard. An experimental melting point (calibrated) of 184°C for the unknown acid was measured. This value most closely correlated with the literature melting point of p-anisic acid, one of the possible twenty compounds on the list. None of the other compounds on the list had melting points within 5°C of the experimental melting point. The unknown was identified as p-anisic acid. Experimental determination of the melting point of an unknown compound is useful for identifying the compound.

Sample C