TARTARIC ACID. 183 



and ammonium chloride. Is deposited from a mixture 

 of lime-water, with an excess of tartaric acid, in the 

 form of large shining crystals. 



Lead tartrate, C 4 HX) 6 Pb, white voluminous pre- 

 cipitate, insoluble in water. Soluble in ammonia. 

 When this solution is boiled, there is thrown down a 



Salt C 4 : Pb 2 = V.-J.O.-I QJL U I I QQ QJ 



Antimonyl-potassium tartrate (Tartar emetic), 

 C 4 H 4 6 (SbO)k + |H 2 0, is prepared by digesting anti- 

 mony oxide with cream of tartar and water. Crys- 

 tallizes in shining octahedral or tetrahedral crystals, 

 which lose their water of crystallization at 108, and 

 become white and opaque. Soluble in 14 parts of 

 water of the ordinary temperature. Acids precipitate 

 from its solution insoluble antimony compounds. 

 Barium, lead, and silver salts precipitate salts which 

 are analogous in composition to tartar emetic. At 

 200 the anhydrous salt loses another molecule of 

 water, and is converted into a salt C 4 H 2 6 SbK (analo- 

 gous to the lead salt C 4 H 2 6 Pb 2 ), from which with the 

 aid of water tartar emetic is regenerated. 



Ethyl tartrate, C 2 H 2 ^g) j caaC 2 !', isformed > 

 when hydrochloric acid gas is conducted into an alco- 

 holic solution of tartaric acid. Liquid ; mixes with 

 water ; not volatile without decomposition. 'Ethyl- 



tartaric add C*H?/QJ|) j ^Qg^ When a solution of 



tartaric acid in absolute alcohol is evaporated, this com- 

 pound is left behind. Crystalline, very deliquescent, 

 easily decomposable acid. 



Ethyl acetyltartrate,C 2 H 2 (gg 2H3 ) j 



and ethyl diacetyltartrate ^ 



CO C 2 H 5 



CO*o'c 2 H 5 resu ^ fr m the action of acetyl chloride 



