I0I2-] BOGERT— CARBON COMPOUNDS. 267 



sideration (be it halogen, amino, carboxyl, or any other group) ? 

 (2) In what manner are its properties influenced by the hydrocar- 

 bon nucleus to which it is attached, and by the other groups pres- 

 ent? (3) How are the properties of the entire molecule likely to 

 be affected by the introduction of such an element or group? To 

 take a single case, by way of illustration, the simple hydroxyl 

 derivatives of the hydrocarbons are numerous and important, and 

 certain well defined characteristics cling to the hydroxyl group irre- 

 spective of the particular hydrocarbon nucleus to which it is 

 attached. Thus, its hydrogen may be replaced by metals (giving 

 alcoholates or phenolates), by hydrocarbon radicles (giving ethers), 

 by acid radicals (giving esters), or the entire hydroxyl may be re- 

 placed by a halogen by acting upon it with a phosphorus halide. 

 That the behavior of this hydroxyl group is influenced, however, 

 by the hydrocarbon nucleus to which it is attached, can be seen at 

 once by comparing a phenol with an alcohol. Further, the presence 

 of the hydroxyl group alters the properties of the entire molecule, 

 as appears immediately when we compare the behavior of benzene 

 and of phenol towards bromine, nitric acid, oxidizing agents, and 

 so forth. 



In this way, the characteristic properties of the different sub- 

 stituents may be firmly fixed in the mind, as well as the general 

 nature of the various classes of organic compounds, and the student 

 learns to associate certain chemical reactions with certain chemical 

 structures, and to reason intelligently from a given structural for- 

 mula as to the chemical behavior of the substance, whether he ever 

 heard of the compound before or not, thus learning not only to 

 deduce correct constitutional formulas, but also to grasp at a glance 

 the chemical properties summarized by such formulas. 



This method of classification saves an immense amount of 

 repetition and brings home very clearly the fundamental proper- 

 ties and relationships of organic compounds, as well as the applica- 

 tion of these properties in analytical and industrial chemistry. 

 Another advantage which follows from this arrangement, is the 

 manner in which it lends itself to laboratory illustration. As all 

 compounds containing the same substituting element or group are 



