358 OXYGENATED COMPOUNDS OF CHLORINE. 



a number almost double that of the heat absorbed by the 

 formation of chloric acid ( 12*0). 



4. Again, for bromic acid (and bromates in solution) 



HBr0 3 (diluted) = HBr (diluted) + 3 , + 15-5 ; 

 and for solid potassium bromate 



KBr0 3 (solid) = KBr + 3 , +121 ; 



values which are essentially the same as for chloric acid in 

 solution (+ 16*8) and for solid potassium chlorate ( + ll'O). 

 Finally, from the elements 



K -f Br(gas) + 3 = KBr0 3 (solid) liberates + 89'3. 



& Hypobromous add. The hypobromites are easily formed 

 by the action of bromine on alkaline solutions. 



It was found, in presence of an excess of alkali, the bromine 

 being liquid, that 



Na 2 (1 equiv. = 3 litres) H- Br (14-318 grms. and 3-365 grms.) at 9 + 6-0 

 K 2 (1 equiv. = 4 litres) + Br (15-801 grms. and 5'734 grms.) at 11 + 5-95 

 BaO (1 equiv. = 6 litres) + Br (12-096 grms. and 12-339 grms.) at 13 + 5-7 



Admitting that diluted hypobromous acid, when combining 

 with bases, liberates the same quantity of heat as hypochlorous 

 acid ; that is to say, + 9*5 ; it may be deduced from the pre- 

 ceding figures that 



J[Br 2 (liquid) + O + water = Br 2 (diluted)], - 67; 

 i[Br 2 (gas) + + water = Br 2 (diluted)], - 31. 



The latter number is essentially the same as what was observed 

 for the formation of hypochlorous acid ( 2'9). 



The alkalies, moreover, dissolve a greater quantity of bromine 

 than that which corresponds to the formation of hypobromous 

 acid. Thus baryta water dissolves in the cold nearly 2 eq. of 

 bromine : or Br 4 for BaO. These facts are explained by the 

 simultaneous formation of alkaline bromides 1 and of hypo- 

 bromites. 



Before pursuing these comparisons further, it is advisable to 

 study the thermal formation of the oxygenated compounds of 

 iodine. 



5. lODIC ACID AND lODATES. 



1. The results will be given which were obtained by the 

 action of iodine on potash, by which are formed hypoiodous and 

 iodic acids. It will then be convenient to examine the reaction 

 of iodic acid on water and alkalies, and also finally to compare 

 the thermal formation of the oxygenated salts derived from 

 chlorine, bromine, and iodine, endeavouring at the same time to 

 deduce therefrom some new data for molecular mechanics. 



1 " Annales de Chimie et de Physique," 5 8 se*rie, torn. xxi. pp. 375, 378. 



