10 
IOWA ACADEMY OF SCIENCES. 
Determination of Iodic Acid . — As the basis for the work 
on iodic acid there was used a tenth normal solution of 
potassium iodate, made from an excellent sample by Merk, 
as the following determinations indicate. Portions of 20 
c.c. of the decinormal solution were digested with potas- 
sium iodide and hydrochloric acid in a well stoppered bot- 
tle in the usual way, the solutions of free iodine thus 
obtained were made up to known volumes and portions 
were titrated with standard decinormal sodium thiosul- 
phate: 
(1) 20 c.c. of iodate solution gave iodine which required 
120.32 c.c. thiosulphate. 
(2) 20 c.c. of iodate solution gave iodine which required 
120.40 c.c. of thiosulphate. 
As well known it is practically impossible to obtain 
commercially, potassium iodide free from iodate. In the 
above experiments five grams of iodide were used in each 
case. The same weight of the iodide digested with hydro- 
chloric acid gave free iodine which required 0.30 c.c. of 
thiosulphate. Applying this correction the volumes of 
thiosulphate required in experiments (1) and (2) are 120.02 
and 120.10, while the theory for a truly decinormal solution 
of potassium iodate would require 120 c.c. 
In the determination of both iodic and bromic acids, the 
iron in the form of washed card teeth, and 25 c.c. 
of dilute, pure sulphuric acid and a measured volume 
of the solution to be determined were placed in a distilling 
flask with a well-ground glass stopper. The side-tube of 
the flask was placed in a small quantity of water in a test 
tube in order to condense and make apparent any iodine 
or bromine that might pass over. At first in the experi- 
ments with iodate, alcohol was used to absorb the iodine, 
but water was substituted after it was found that with 
proper regulation of the temperature the amounts of iodine 
or bromine that passed over were practically negligible. 
On placing the substances together in the flask iodine was 
' at once liberated, and considerable quantities soon settled 
upon the bottom of the flask. At room temperature the 
