30° C. 70° C. 100° C.
"Uranium" required 18.0 c.c. 18.5 c.c. 18.5 c.c. 18.7 c.c.
~Effect of Varying Bulk.~--These experiments were like those last
mentioned, but were titrated boiling, and the volume was varied:--
Bulk 50.0 c.c. 100.0 c.c. 200.0 c.c. 300.0 c.c.
"Uranium" required 14.0 " 14.0 " 14.5 " 15.0 "
Considerable variations in bulk are to be avoided.
~Effect of Varying Sodium Acetate.~--These experiments were carried out
like those last noticed, but the bulk was 150 c.c., and varying amounts
of sodic acetate were added in excess of the quantity used in the
experiments previously described:--
Sodic acetate added 0 gram 1 gram 10 grams 20 grams
"Uranium" required 14.5 c.c. 14.5 c.c. 16.0 c.c. 18.0 c.c.
It is evidently important that the quantity of this salt present in each
titration be measured out, so as to avoid variation.
~Effect of Varying the Sodium Acetate and Acetic Acid Solution.~--Acetic
Acid also affects the results, but in the opposite direction, by
preventing the precipitation of uranium arsenate. With varying volumes
of the solution now under notice, the results were:--
Solution added 0.0 c.c. 5.0 c.c. 10.0 c.c. 15.0 c.c.
"Uranium" required 14.
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