66 Biological Chemistry. 



The chief reason for assigning this constitution is the fact 

 that one of the hydrogen atoms behaves differently to the 

 three others. If an alcohol is treated with metallic sodium 

 or potassium, one and only one atom is replaced by the 

 metal forming, with evolution of hydrogen, a compound 

 with the formula CH 3 ONa, which can be decomposed by 

 water according to the equation 



CH 3 ONa + H 2 = CH 3 OH + NaOH 



This reaction is analogous to the action of sodium on water, j 

 which leads to the formation of sodium hydroxide, or 

 caustic soda, NaOH. The sodium derivative of methyl al- 

 cohol may be considered as analogous to sodium hydroxide, 

 the hydrogen of the latter substance being regarded asj 

 replaced by the methyl group. It is known as sodium j 

 methoxide. The analogy will be clear from the following! 

 formulae : 



NaOH NaOCH 3 



Methyl alcohol, if such conceptions are correct, can then' 

 be regarded as an analogue of water, in which onei 

 hydrogen is replaced by a methyl group 

 H\ C5H 3 K 



H> H > j 



Furthermore, the fact that such a group as the methyl , 

 exists in the molecule is indicated by its preparation froiri 

 methyl chloride (monochlormethane) ; in this compound)! 

 three hydrogen atoms are directly united to a carbonj 

 atom. Again, the oxygen and one hydrogen atom ani 

 together replaceable by chlorine, and methyl chloride thuj ; 

 obtained may be regarded as an analogue of hydroger 

 chloride 



HC1 CH 8 C1 



A whole series of carbon compounds is in fact known, o:| 



