MONOBASIC FA TTY A CIDS. 329 



to this basic acetate more acetic acid, the neutral acetate is obtained, 

 but this may be made directly also by dissolving cupric hydroxide 

 or carbonate in acetic acid. It forms deep green, prismatic crystals, 

 which are soluble in water. 



By boiling verdigris with arsenous oxide, cupric aceto-arsenite, 

 3CuAs 2 O 4 + Cu(C 2 H 3 O 2 ) 2 , is formed, which is the chief constituent 

 of emerald green or Schweinfurt green, a substance often used as a 

 coloring matter. Paris green is of a similar composition, but less 

 pure. 



Ciller-acetic acids. By treating acetic acid with chlorine, either one, two, 

 or three hydrogen atoms may be replaced by this element, when either mono-, 

 di-, or tri-chlor-acetic acid is formed. Trichlor-acetic acid, C 2 C1 3 HO 2 , is a color- 

 less, crystalline substance, which fuses at 55 (131 F.), and boils at 195 C. 

 (383 F.). 



Acetone, C 3 H 6 O (Dimethyl -ketone). This compound is obtained 

 by the destructive distillation of acetates (and of a number of other 

 substances). The decomposition which calcium acetate suffers may 

 be shown by the equation : 



CH 3 COO\ C ._ CH 3 \ CO , c co 

 CH 3 COOX CH 3 x 3> 



Calcium acetate. Acetone. 



The above graphic formula of acetone shows this substance to be 

 dimethyl carbonyl, or carbon monoxide whose two available affini- 

 ties have been satisfied by two methyl groups. Acetone is the repre- 

 sentative of a series of compounds known as acetones or generally 

 as ketoneSj the general composition of which may be assumed to be 

 R_C E 



|| , II representing in this case any univalent radical. 

 O 



Acetone is a colorless liquid, boiling at 58 C. (136 F.), miscible 

 with water, alcohol, and ether in all proportions ; it has a peculiar 

 ethereal, somewhat mint-like odor. 



Butyric acid, HC 4 H 7 2 . Among the glycerides of butter those of butyric 

 acid are found ; they exist also in cod-liver oil, croton oil, and a few other fatty 

 oils ; some volatile oils contain compound ethers of butyric acid ; free butyric 

 acid occurs in sweat and in cheese. It may be obtained by a peculiar fermen- 

 tation of lactic acid (which itself is a product of fermentation), and is also 

 generated during the putrefaction of albuminous substances. Butyric acid is 

 a colorless liquid, having a characteristic, unpleasant odor; it mixes with 

 water in all proportions. 



Valerianic acid, HC 5 H 9 O 2 ( Valeric acid). This acid occurs in 

 valerian root and angelica root, from which it may be separated ; it 



