c. 19.2 c.c. 15.5 c.c.
These show that the temperature should not much exceed 20°.
~Effect of Exposure of the Iodine Solution.~--Twenty c.c. of the iodine
were diluted to 100 c.c., and exposed for varying lengths of time in
open beakers at the ordinary temperature, and then titrated.
Time exposed -- 1 day 2 days 3 days
"Hypo" required 20.4 c.c. 16.1 c.c. 13.6 c.c. 9.4 c.c.
~Effect of Varying Bulk.~--These experiments were carried out in the
usual way, bulk only varying.
Bulk 100.0 c.c. 200.0 c.c. 300.0 c.c. 500.0 c.c.
"Hypo" required 20.4 " 20.4 " 20.4 " 20.4 "
~Effect of Varying Acid.~--These experiments were under the usual
conditions, the bulk being 100 c.c. The results were--
Acetic acid -- 1.5 c.c. 30.0 c.c.
"Hypo" required 20.4 c.c. 20.7 " 20.7 "
Hydrochloric acid -- 1.5 c.c. 15.0 c.c.
"Hypo" required 20.4 c.c. 20.6 " 20.9 "
Sulphuric acid -- 0.5 c.c. 20.0 c.c.
"Hypo" required 20.4 c.c. 20.7 " 15.2 "[86]
Nitric acid -- 0.5 c.c. 10.0 c.c.
"Hypo" required 20.4 c.c. 21.5 " could not be titrated.
In the application of this titration to the assay of manganese ores,
hydrochloric and hydriodic acids are the only ones likely to be present.
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