274 CONSIDERATION OF CARBON COMPOUNDS. 



but are not alcohols in the sense in which this term is used. 

 The more important substances belonging to this group will be 

 considered later. 



QUESTIONS. 



391. What is the general constitution of alcohols, and what is the 

 difference between monatomic, diatomic, and triatomic alcohols? 



392. How do alcohols occur in nature? 



393. By what processes may alcohols be formed artificially, and how 

 may they be separated from their combinations ? 



394. State the general properties of alcohols. 



395. Mention names and composition of the first five members of 

 alcohols of the general composition C n H 2n + jHO. 



396. By what process is methyl alcohol obtained, under what other 

 names is it known, and what are its properties ? 



397. Describe the manufacture of pure alcohol from sugar. 



398. Give the alcoholic strength of the alcohol and diluted alcohol of 

 the U. S. P., and also of spirit of wine, proof-spirit, light wines, heavy 

 wines, beers, and spirits. 



399. What are the general properties of common alcohol? 



400. What is glycerine, how is it found in nature, how is it obtained, 

 and what are its properties ? 



41. ALDEHYDES. HALOID DERIVATIVES. 



Aldehydes. The name aldehyde is derived from alcohol de- 

 hydrogenatum,' referring to its method of formation, viz., by 

 the removal of hydrogen from alcohols, as, for instance : 



C 2 H 6 O 2H = C 2 H 4 O. 



Ethyl Acetic 



alcohol. aldehyde. 



This removal of hydrogen ma} T be accomplished by various 

 methods, as, for instance, by oxidation of alcohols, when one 

 atom of oxygen combines with two atoms of hydrogen, forming 

 water, whilst an aldehyde is formed at the same time. Alde- 

 hydes, when further oxidized, are converted into acids; aldehydes 

 are, consequently, the intermediate products between alcohols 

 and acids, and are frequently looked upon as the hydrides of the 

 acid radicals. Only a few aldehydes are of practical interest, 

 as, for instance, benzoic aldehyde, which substance will be 



