126 CHEMICAL PROPERTIES AND COMPOSITION 



These specific differences are found again in compounds 

 of the types 



C w H 2n+2 , C rt H 2w+] OH, C W H 2M4 . 1 COH, 



of which the first in association with methane are distin- 

 guished by their small tendency to reaction or oxidation, 

 and for that reason called paraffins. The second group 

 in which hydroxyl is present is that of the alcohols, and 

 can be oxidized by a mixture of chromic and sulphuric 

 acids, which is an appropriate means of preparing the 

 higher oxidation products, aldehydes and acids. Further, 

 in the aldehyde group we have a new characteristic in the 

 faculty of reducing silver oxide and formation of a silver 

 mirror with ammoniacal silver oxide solution. 



Another fact is connected with this, viz. that in complex 

 compounds oxidation takes place just in the most highly 

 oxidized places, provided the carbon there is associated 

 with hydrogen. If only one carbon atom is oxidized, as 

 in alcohol and aldehydes, 



H 3 CCH 2 OH, H 3 CCOH, 



the new oxygen enters there, forming aldehyde and acetic 



acid, 



H 3 CCOH, H 3 CCOOH, 



instead of glycol and oxaldehyde, 



CH 2 OHCH 2 OH, CH 2 OHCOH. 



If there are more oxidized as in aldol, 



CH 3 CHOHCH 2 COH, 



the new oxygen enters at the most oxidized spot, forming 

 oxybutyric acid, 



CH 3 CHOHCH 2 COOH 



and not the ketone aldehyde 



CH 3 COCK,COH. 



Something similar is observed in the inorganic region, 

 but cannot be followed out in such detail, on account of 



