300 
SELECTED ARTICLES. 
bility; the least increase of temperature suffices to decompose 
them into chlorates and chlorides, oxygen gas being given off, 
according to Balard; when alkaline, their solutions may be 
evaporated without being decomposed. 
They can easily be distinguished from the chlorites, by the 
facts, that when treated by acids they give off hypochlorous 
acid, either pure or mixed with chlorine, and that when pre- 
viously mixed with a metallic chloride, chlorine alone is libe- 
rated from them by the action of acids; which is owing to the 
mutual decomposition of hydrochlorous and hydrochloric 
acids, as expressed by the following formula: 
Ch 2 0+2HCh=H 3 0-h4Ch. 
The same result is not observed when mixtures of chlorites 
and chlorides are treated in the same manner, because hydro- 
chloric acid has no action on chlorous acid. An analogous 
result is presented us in the action of acids on a mixture of 
chlorides and chlorates, by which chlorous acid, mixed with 
its own volume of chlorine, is evolved with effervescence, 
even at ordinary temperature; this reaction of hydrochloric 
and chloric acids, is expressed by the following formula: 
Ch 2 5 + 2HCh = H 2 + 2Ch0 2 +2Ch. 
So that the product is a mixture of equal volumes of chlorous 
acid and chlorine, and not water and chlorine, as generally 
stated. This reaction greatly facilitates the decomposition of 
these salts by acids; for sulphuric acid, diluted with its own 
volume of water, which at the ordinary temperature has no 
action either on the chlorate of potassa or the chloride of po- 
tassium, decomposes them with ease when mixed as stated 
above. For the same reason, a mixture of iodide of potassium 
and iodate of potassa is decomposed by the feeblest acids, even 
by carbonic acid, with precipitation of iodine, as observed by 
Gay Lussac, the hydriodic and iodic acids mutually decom- 
posing each other. 
This property, which the hypochlorites possess, of giving 
off chlorine by the action of acids when previously mixed 
with metallic chlorides, has contributed in no small degree to 
strengthen the opinion, that the chlorides of oxides are mix- 
