MONOBASIC FATTY ACIDS. 285 



Analytical reactions. 



1. Any acetate heated with sulphuric acid evolves acetic acid, 

 which may be recognized by its odor. 



2. Acetic acid or acetates heated with sulphuric acid and 

 alcohol give a characteristic odor of acetic ether. 



3. A solution containing acetic acid or an acetate carefully 

 neutralized turns deep red on the addition of solution of ferric 

 chloride, and forms, on boiling, a reddish-brown precipitate of 

 an oxyacetate of iron. 



Potassium acetate, Potassii acetas, KC 2 H 3 2 = 98. Sodium acetate, 

 Sodii acetas, NaC.,H 3 2 .3H,0 = 136, Zinc acetate, Zinci acetas, 

 Zn2(C 2 H 3 2 ).3H 2 = 236.9. These three salts may be obtained 

 by neutralizing the respective carbonates with acetic acid arid 

 evaporating the solution ; they are white salts, easily soluble in 

 water. 



Ferric acetate, Fe 2 6(C 2 H 3 2 ). A 33 per cent, solution of this 

 salt is the Liquor ferri acetatis of the U. S. P. It is made by dis- 

 solving freshly precipitated ferric hydrate in acetic acid ; it is a 

 dark, red-brown, transparent liquid of a specific gravity of 1.16. 



Lead acetate, Plumbi acetas, Pb2(C 2 H 3 2 ).3H 2 = 378.5 (Sugar 

 of lead), is made by dissolving lead oxide in diluted acetic acid. 

 It forms colorless, shining, transparent crystals, easily soluble in 

 water; on heating, it melts and then loses water of crystalli- 

 zation ; at yet higher temperatures it is decomposed ; it has a 

 sweetish, astringent, afterwards metallic taste. 



When a mixture of lead acetate and lead oxide is digested or 

 boiled \vith water, the acetate combines with the oxide, forming 

 a basic lead acetate, Pb.2(C 2 H 3 O 2 ) + 2PbO, a 25 per cent, solution 

 of which is the Liquor plumbi subacetatis, or Goulard's extract, 

 whilst a solution containing about 1 per cent, is the Liquor 

 plumbi subacetatis dilutus, or lead-water. 



Cupric acetate, Cupri acetas, Cu2(C 2 H 3 2 ).H 2 = 199.2 (Acetate 

 of copper). The commercial verdigris is a basic acetate of copper, 

 Cu2(C 2 H 3 2 ).CuO, made by the action of diluted acetic acid and 

 atmospheric air on metallic copper. By adding to this basic 



