480 Dr. Harry C. Jones on the 



complete dissociation, then becomes greater and greater 

 with increase in concentration, and finally diminishes as we 

 approach no dissociation. This is clearly seen in curve 8 

 (Plate VI.), which rapidly approaches curve 7, while curve 9 

 rises much less rapidly. 



Of the four acids investigated, the two monobasic (HC1 

 and HN0 3 ) dissociate to a greater degree than the dibasic 

 (H 2 S0 4 ), and this in turn more than the tribasic (H 3 P0 4 ). 



Potassium Hydroxide. — The preparation was freed from 

 carbonate, with special care, by solution in alcohol. As has 

 been pointed out, these results from the hydroxides cannot be 

 regarded as thoroughly accurate, on account of the exposure 

 to the air and the absorption of small amounts of carbon 

 dioxide. When the hydroxides were under investigation, all 

 the water was boiled just previous to using and before the 

 drop of alkali was added. The water used in the preparation 

 of the original solution was also boiled and cooled, protected 

 from the carbon dioxide of the air, that the above error might 

 be reduced to a minimum. 



The results show that potassium hydroxide is dissociated to 

 very nearly the same degree as potassium chloride, while both 

 are dissociated less than the hydrochloric acid. The dissocia- 

 tion of the hydroxide is greater than that of the sulphate, 

 which in turn is more dissociated than the free sulphuric acid. 



Sodium Hydroxide. — The hydroxide used was prepared by 

 allowing sodium to act upon water. The difference in the 

 dissociation of sodium and potassium hydroxide is so slight 

 that it is probably the result of error caused by the presence 

 of unequal small quantities of carbonate. This difference 

 increases somewhat with increase in concentration ; but this 

 increase is so small that doubt exists as to whether it repre- 

 sents an actual difference. The relation between the degree 

 of dissociation of the hydroxides, acids, and salts, which exist 

 in the case of potassium, hold also for sodium. 



Ammonium Hydroxide. — The conductivity of ammonium 

 hydroxide has shown that the dissociation is only a small part 

 of that of the other hydroxides. The freezing-point results 

 lead to the same conclusion, yet the chloride of ammonium 

 undergoes the same dissociation as the chlorides of sodium 

 and potassium. This very small dissociation is seen in curves 

 5 and 6 (Plate VII.), which rise very rapidly as compared 

 with the curves for the other hydroxides. 



The solutions of ammonium hydroxide were exposed to the 

 same error from the carbon dioxide of the air as the other 

 hydroxides, and an additional error from the volatility of the 

 base. This can be disregarded for the most dilute solutions, 





