﻿53(5 Oxidation of Phosphorus, Sulphur, and Aldehyde. 



much more easy to cause an electric discharge (without elec- 

 trodes) to pass through moist oxygen than through the gas 

 when it is dry. The moisture apparently favours the forma- 

 tion of the atoms which carry the discharge. It must be 

 confessed, however, that this view does not explain the 

 formation of ozone which accompanies the oxidation of phos- 

 phorus, not only in moist oxygen but also, according to 

 Marchand*, in the dry gas. 



The complicated nature of the reaction which takes place 

 when phosphorus is oxidized in presence of water makes it 

 impossible to do more than guess at an interpretation of the 

 results obtained. Perhaps, however, the different nature of 

 the equation representing the connexion between the velocity 

 of the reaction and the pressure of the oxygen is due to the 

 water taking part in the reaction. 



The irteresting fact that a pressure of oxygen exists at 

 which the oxidation has a maximum velocity in the case of 

 phosphorus, and perhaps also in that of aldehyde, requires 

 further investigation before any satisfactory attempt can be 

 made to account for it. 



In conclusion it is perhaps worth noticing that, in one or 

 two other cases which have been studied by other observers, 

 the results are in harmony with the theory of Williamson. 



Le Chatelier f has shown, using the results of Hautefeuille 

 and Margottet, that, at constant temperature, the equilibrium 

 which occurs when chlorine, hydrogen, and oxygen are 

 exploded together can be represented by the expression 



log ^*^ HC1 > = const., 



i ? (Cl 2 ) X i ? (H 2 0) 



in which p {0 ^ ^>( H ci) • • • are the partial pressures in the 

 equilibrium of the oxygen, hydrochloric acid, .... 



If we suppose the reaction to occur between dissociated mo- 

 lecules we may write the reaction which occurs as follows : — 



2HC1 + ^Z± 2C1 + H 2 0, 

 which would correspond to the equation 



log 4^(M) = ^ 

 P{OJ X i 9 (H 2 0) 



which is the equation given by Le Chatelier after dividing 

 both sides by 2. 



In conclusion, my best thanks are due to Prof, van't HofF, 

 in whose laboratory the foregoing work was done, for his 

 advice and assistance during its progress. 



* Journ. prakt. Chem. 1. p. 1 (1850). 

 f Comptes Rendus, cix. p. 665 (1889). 



