258 OXY-ACIDS AND SALTS OF THE NON-METALS- Bromic and Iodic Acids. To a globule of carbon di-
sulphide in a test tube add a few drops of bromine water until,
after shaking, the globule has assumed a distinct red color.
Add 5 cc. water and then chlorine water, a few drops at a
time, shaking after each addition. The red color bleaches
and finally disappears altogether.
Repeat, substituting iodine for bromine, and note that the
deep violet color, which the free iodine imparts to the globule
of carbon disulphide, is likewise bleached on shaking the glob-
ule with chlorine water.
Recall Experiment 11, page 165, which showed that chlorine
oxidizes bromide and iodide respectively to free bromine and iodine.
The present experiment carries the oxidation still further and raises
the valence of each element to +5.
5C1 2 + Br 2 + 6H 2 O -»• 2HBrO 3 + 10HC1
5C1 2 + I 2 + 6H 2 O -»2HIO 3 + 10HC1Bromic and iodic acids are colorless; they are very soluble in
water, and highly ionized.- Properties of Potassium Chlorate, (a) Heat some
potassium chlorate in a test tube. It melts and soon after-
wards the melted salt effervesces. A glowing splinter thrust
into the gas bursts into flame.
(6) Place a very small crystal of potassium chlorate on a
watch glass, (Danger! use of a larger amount may cause a
violent explosion), place 2 drops of 36 iV H 2 SC>4 on an adjacent
part of the glass and let it flow until it touches the crystal.
The latter dissolves with effervescence, a deep yellow gas
with a very strong odor somewhat resembling that of chlorine
being formed. Part of this gas dissolves in the sulphuric acid
coloring it a deep brownish yellow.
(c) Add 6 N H 2 SC>4 to a dilute potassium chlorate solution.
In (c) the ions of chloric acid are brought together and thus a
solution of chloric acid containing also the ions of potassium sul-
phate is obtained. Chloric acid is a soluble, highly ionized acid
of a stability comparable to that of nitric acid.
In (b) chloric acid is formed, but the concentrated sulphuric acid
acts as a dehydrating agent.. The oxide C1 2 O 6 , which is obviously