OF THE SYSTEM NAPHTHALENE-PHENOL. 11 



or C, =^_ + ^_+^^+,^_-^_ + ^^ (17) 



The value of Q' cau now be found from (16), and the degree 

 of dissociation 



becomes known. 



The heat of fusion of phenol as determined in the usual 

 manner, is the sum of the heat of fusion proper and of the heat 

 of dissociation. Q', the ordinary molecular heat of fusion (for 

 the molecular formula CgHgO), can be expressed by the following 

 equation : 



SQ' = (), + «D (18) 



Since Q' as well as « and Q are known, Qi can be evaluated. 

 Ti can now be determined by equation (13) 



^' ^ -q^VÉtJiii cv ^^^ "^ 



where T^l is the melting point of phenol. 



4. Experimental Details. 



The method employed in the determination of the fusion 

 points was quite similar to the cryoscopic method of Beckmann. 

 The outer vessel which served as the bath was a large beaker 

 of about three litre capacity and was nearly filled with water. 

 The temperature of the bath was kept a few degrees below the 

 fusion point to be observed. After some practice this could be 

 managed with tolerable certainty by regulating the height of the 

 flame of a burner placed beneath the vessel. 



