Burnt Alum is prepared by subjecting ammonium alum or potassium alum to a temperature not exceeding 2000 C, until the water of crystallization has been expelled. When recently prepared it should contain not less than 96.5% A1NH4 (or K) (S04)2.

Properties:

Appearance................................................................................................

Solubility:

Color......................................................................

Cold H20....................................................................................

Odor ...................................................................

Hot H20 ...................................................................................

Taste .............................................................................................................-

C2H5OH..........................................................................................

Incompatibilities: To alum solution add solution of

NaOH..................................................................

Pb. Acet .......................................................................

Na2B407 .................................................................

Ca(OH)2 ............................................................................................................

NaHCO3................................................................

HgCl2 .......................................................................

Ac. Gall ...................................................................

Ac. Tart ........................................................................

Alum is a mild cauterant, an irritant astringent, and a styptic.