In CHM 246 you will be given at least two unknowns to completely identify:

1. On the computers, any unknown could be solid or liquid

 2. The solid, analyzed in lab, will be a carboxylic acid, or a phenol.

ACIDS / PHENOLS

Solubility tests: Early in the analysis you will perform solubility tests:

Water insoluble acids are soluble in weak base (bicarbonate). Water insoluble phenols are soluble in strong base (hydroxide), sometimes with a color change.

In either case, we are talking about an enhanced solubility. Acids are more soluble in bicarb than in water; phenols are more soluble in (or react with) NaOH more than water or bicarb. Phenols can be confirmed with the ferric chloride test (see below).

Sodium Fusion Tests: This test detects presence of nitrogen. Your unknown solid may, or may not, contain N. The nitrogen, if present, could be an amine, a nitro group, a nitrile, etc. In the wet labs, the sodium fusion test will not be done.
(NB - On the computers, your unknown may have Cl, Br, N or any combination of these for any unknown. Be sure to run Na fusion.)

Melting Points: An important part of the characterization of the unknown is a precise and accurate melting point. Precision: Be sure that melting points are performed on small, well-packed samples. Be sure that the rate of heating near the melting point is 1deg per minute. Accuracy: The most sophisticated MP apparatus is worthless unless it is calibrated. Reagent grade benzoic acid is available for this purpose. (Computer mp's are usually correct.)