230 Mr. Williamson on the 



What now can be the cause of potash combining with a 

 less quantity of chlorine than is the case with barytes? This 

 arises probably from the stronger afiinity of potash for chloric 

 acid, which causes a decomposition of hypochlorous acid, by 

 which chloric acid is formed and chlorine set free. Hence it 

 is evident that by the formation of a small quantity of chloric 

 acid the total quantity of chlorine in the liquid must be much 

 diminished. 



I now treated carbonate of potash in a similar manner with 

 chlorine, and obtained the well-known liquid, possessing, from 

 the first action of the chlorine, the smell and other properties 

 of free hypochlorous acid, a considerable quantity of which 

 was carried away by the escaping carbonic acid. Now, if this 

 liquid be heated for some time in a water-bath, the hypochlo- 

 rous acid is completely destroyed, chlorine is disengaged, 

 and the liquid now contains a mixture of chloride of potas- 

 sium with chlorate of potash. As the hypochlorous acid was 

 from its first formation uncombined, the chloric acid must 

 have, in all probability, been formed by a different process 

 from that which took place in the preceding instance, where, 

 by the action of chlorine on a hypochlorous acid salt, chloric 

 acid formed, partly by taking the oxygen directly from the 

 base, partly, perhaps, by a decomposition of hypochlorous 

 acid. We here have a mixture of hypochlorous acid with 

 chloride of potassium ; after heating which we find part of 

 the chloride of potassium is changed into chlorate of potash. 



Now if this be the case, I must obtain the same result by 

 treating a solution of chloride of potassium with hypochlorous 

 acid. The experiment was made in the following manner : — 

 In a concentrated aqueous solution of hypochlorous acid were 

 dissolved crystals of chloride of potassium, and the mixture was 

 heated in a water-bath until chlorine ceased to be disengaged. 

 This liquid deposited, on cooling, scales of chlorate of potash, 

 which was also easily detected in the mother-liquid. 



This process must not be considered as a direct oxidation of 

 the chloride, for peroxide of hydrogen produces no such effect. 



It is well known that aqueous hypochlorous acid has a great 

 tendency, especially when heated, to form chloric acid, setting 

 free chlorine. Now when chloride of potassium is present, 

 this chloric acid, in the moment of its formation, decomposes 

 the chloride, setting free its chlorine, the metal oxidating 

 itself at the expense of hypochlorous acid. 



On treating carbonate of soda with chlorine I obtained 

 similar results, with the diiference, that chloric acid formed 

 even more easily than was the case with potash, and conse- 

 quently the total content of chlorine in the liquid was less. 



