Structure of Simpler Organic Compounds. 81 



p. 58), in that the two chlorine atoms are united to the 

 same carbon atom. 



Furthermore, aldehydes readily form addition products, 

 the production of which can be readily explained on the 

 basis of the above formula. 



Thus when aldehyde is treated with sodium hydrogen 

 sulphite (bisulphite) it forms a crystalline compound of 

 the formula CH 3 CHO-NaHSO 3 ; with ammonia it forms 

 the compound CH 3 CHONH 3 ; with hydrocyanic acid it 

 forms a cyanhydrin, CH 3 CHO-HCN ; and with alcohol at 

 100 it forms acetal. To these addition products the 

 following constitutional formulae may be assigned : 



/OH /OH /OH 



CH a CH< CH 3 -CH< CH 3 CH< 



/OC 2 H 5 

 and CH 3 CH< 



X)C 2 H 5 



The aldehydes generally are very reactive substances. 

 As they can be produced from primary alcohols by oxida- 

 tion, so conversely, by treatment with nascent hydrogen, 

 they can be reduced again to alcohols 



Furthermore, on oxidation they give rise to a " fatty " 

 acid, containing the same number of carbon atoms 



This oxidation is best accomplished by means of silver 

 oxide, Ag 2 0, which is thereby reduced to metallic silver 



CH 3 CHO + Ag 2 = Ag 2 + CH 3 C0 2 H 



By virtue of the readiness with which the aldehydes 

 are oxidized, they readily act as " reducing agents." Thus 

 an alkaline solution of cupric salts is reduced to cuprous 

 oxide (Fehling's solution, see p. 195), and a silver mirror 



(1,907) 6 



