360 OXYGENATED COMPOUNDS OF CHLOKINE. 



thermometer can reveal to us, require to be determined by 

 figures : 



i[I 2 + K 2 (1 equiv. = 2 litres)] at 14 



First effect : absorption ... . . ^ ... 0*58 



Second effect : liberation + 0'65 



Total effect ... +0-07 



I 2 + K 2 (1 equiv. = 4 litres)] at 15 



1 'ing half the iodine : first effect - 0'38 



second effect +0-30 



Total effect ,,. -0-08 



Adding the surplus of iodine : first effect ... - 0-19 



second effect .,. +0-17 



Total effect ... - 0-02 



The total effect of the two effects united ... - 0-10 



I 2 + K 2 (1 equiv. = 8 litres)] at 15 



"irst effect - 1-27 



Second effect +1-18 



Total effect ,,. - 0-09 



Let us note here that the first thermal effect, namely, the 

 cooling, does not afford an exact measure of the heat absorbed 

 in the corresponding reaction (formation of hypoiodite), but only 

 a superior limit, since the fresh rise in the temperature succeeds 

 too rapidly. 



7. It being admitted that the final product of the preceding 

 reaction is potassium iodate in solution 



61 (solid) -f 3K 2 (diluted) = KIO 3 (dissolved) + 5KI (dilute); 

 and also that the formation of diluted potassium iodide 

 K -f I -f water = KI (diluted) liberates + 747 Cal.; 



we pass from this to anhydrous iodic acid, monohydrated acid, 

 and solid potassium iodate, by means of the following data : 



(a) Potassium iodate in solution. 



i[2HI0 3 (1 equiv. = 1 litre) + K 2 (1 equiv, = 1 litre) = 2KI0 3 



(dissolved)], at 13 + 14-30 



i[2HI0 3 (1 equiv. = 4 litres) + K 2 (1 equiv. = 4 litres) = 2KI0 3 



(dissolved)] ... ., + 14-25 



These numbers slightly exceed the heat of neutralisation of 

 nitric acid by potash. This excess was ascertained by the 

 method of reciprocal double decompositions ; that is, by treating 

 alternately dissolved potassium iodate with diluted nitric acid, 

 and potassium nitrate with iodic acid, in presence of the same 

 quantities of water. 



(b) Solution of hydrated iodic acid. 



HI0 3 (crystallised) (1 part to 45 parts of water) 4- water, at 12, 



- 2-67. 



