

Equilibrium in Mixed Electrolytes. 351 



change, and enabled the mixtures to arrive at a fixed state. 

 The results of previous experiments (Phil. Mag. Jan. 

 1892, p. 49) show that the action of the higher temperature 

 was upon the halogen present. In all cases of heating- 

 aqueous solutions, either of CI, Br, or iodine alone (ibid.), or 

 of Cl + (KBr+KI), Br + (KCl + KI), or I+(KCl + KBr), 

 Table IV. ; Br + KHO, with a positive metal of aluminium 

 or of tin, Tables XI. and XII. ; C1+KH0, Br + KHO, or 

 I + KHO, with zinc as a positive metal — a relative loss of 

 electromotive force took place, and a more fixed state of 

 chemical equilibrium was attained. 



6. The results of Table I. show that if the ingredients of a 

 mixture of a halogen and a salt in water were in the propor- 

 tion of their chemical equivalents, the complete change and 

 attainment of a fixed condition of equilibrium was promoted. 

 If, however, as in Table II., the saline ingredient was in 

 excess, the change to a fixed state of chemical equilibrium was 

 retarded. But if, as in Tables V. and VI. , the electro- 

 negative one was in excess, the changes were not retarded. 



7. Mixtures of halogens and acids in chemically equivalent 

 proportions, as in Table VIIL, acted much like those of 

 halogens and salts in Table I., i. <?., their solutions at once 

 attained a fixed or final state of chemical equilibrium on 

 mixing ; but an additional acid, like an additional salt, 

 retarded the chemical change (see Table X.). 



8. Comparison of the results given in Tables I. and II. 

 with those in Tables VII. and IX., shows that whilst doubling 

 the proportion of salt to halogen retarded the change, 

 doubling that of the halogen had no such effect. 



9. Comparison also of the results given in Tables XIII. , 

 XIV., and XV. with those obtained with solutions of the 

 halogens alone (Phi!. Mag. Jan. 1892, p. 49) shows that 

 the addition of a caustic alkali to a solution of a halogen 

 considerably retarded the rate of change which occurred on 

 heating. An inspection of the results in Tables XIII. , XIV., 

 and XV., further shows that the greatest retardation occurred 

 with chlorine and the least with iodine ; probably because the 

 chlorine had the largest amount of molecular motion to be 

 retarded. 



10. The leading idea in all these cases is the degree of 

 freedom of molecular motion, and the most general conclusion 

 is, that the smaller the degree of freedom of such motion of 

 the halogen molecules, the greater the retardation of chemical 

 change ; heat therefore increases, and the presence of dis- 

 solved alkalies, salts, or acids decreases the rate of change 

 and retards the attainment of a fixed state of chemical 

 equilibrium. 



2 B2 



