ON THE HALOGEN HYDRIDES AS CONDUCTING SOLVENTS. 



123 



found, for example, that ether enters into combination with the three halogen acids, 

 forming compounds which have the following formulae : 



(C 3 H 5 ) 2 0, 5HC1, M.P. = -120, 

 (C 3 H 5 ) 2 0, HBr, M.P. = - 42, 

 (C 2 H 5 ) 2 O, HI, M.P. = - 18. 



We have explained the formation of these and similar compounds by assuming the 

 existence of tetrad oxygen at these low temperatures. 



The compound of ether and hydrogen bromide would thus have the formula 



p 2 Tj /O\r>,> an d might be expected to undergo electrolytic dissociation. 



Quantitative Measurements of Conductivity. 



The pure solvents are extremely poor conductors of electricity, their specific 

 conductivity being as follows : 



Hydrogen chloride about 0*2 x 10~", 



bromide 0'05xlCr 8 , 



iodide 0'2 x 1(T 6 , 



,, sulphide ,, O'l x 10~ li , 



that of the purest water being - 04 x 10~ 6 . 



The resistances are thus much greater than that of an ordinary sample of distilled 

 water. 



The majority of the measurements of conductivity were made in an apparatus 

 (fig. 2) consisting of a graduated test-tube with fixed electrodes. 



Fig. 2. 



Fig. 3. 



A sufficient quantity of the solvent was first placed in the conductivity vessel and 

 a weighed quantity of the substance under investigation introduced by means of a 



E 2 



