226 
ON THE ACTION OP NITRIC ACID, ETC. 
acid. The action of nitric acid upon chlorate of soda, is the 
same as upon chlorate of potassa. The chlorine and oxygen 
are set free in a state of mixture, and every four atoms of chlo- 
rate of soda, yield three of nitrate, and one of hyperchlorate. 
The hyperchlorate of soda is a very soluble salt, and crystal- 
lizes in small rhombs. It is readily decomposed by heat, 
but is unacted upon by hydrochloric acid. It deliquesces by 
exposure to the air. 
The action of nitric acid on an iodate is very different 
from that on a chlorate, and is illustrated in the case of 
iodate of potassa. When iodate of potassa is boiled for some, 
time with a large excess of nitric acid, it is decomposed into 
potassa and iodic acid ; the potassa combines with the nitric 
acid, and the iodic acid is deposited from the solution in 
minute, hard, and transparent crystals. If the acid solu- 
tion of nitre, containing the iodic acid, be then evaporated, 
a reaction takes place; the iodic acid decomposes half the 
nitre, liberating the nitric acid, and combines with the potassa, 
forming biniodate of potassa. This change is completed 
when the mixture is dry, and if the heat be then withdrawn, 
a definite mixture of biniodate and nitrate is obtained. If 
the heat be continued, a still further change occurs; the iodic 
acid expels the whole of the nitric acid, and neutral iodate 
remains. By acting on iodate of soda with nitric acid, 
Professor Penny has obtained a biniodate of soda, and by 
adding a considerable excess of iodic acid to a solution of 
iodate of soda, he ha^ found a teriodate of soda. 
Both these salts are anhydrous. The biniodate of potassa 
contains one atom of water. He also finds that crystals of 
iodate of soda contain different quantities of water accord- 
ing to "the strength of the solution from which they were 
deposited. He obtained it with 2, 4, 6, and 8 atoms of 
water. 
The action of nitric acid upon bromate of potassa was 
next examined, and found to differ remarkably from its ac- 
tion on the chlorate and iodate. Neither hyperbromate 
nor bibromate is produced, but merely nitrate of potassa. 
