Selenious Acid USP Grade
H2SeO3 -- 128.97
Selenium dioxide, monohydrated.
Selenious acid [7783-00-8].
Selenious Acid contains not less than 93.0 percent and not more than 101.0 percent
of H2SeO3.
Identification
A: Dissolve about 50 mg in 5 mL of water, add about 100 mg of sodium bicarbonate,
and mix: gas bubbles develop.
B: Dissolve about 50 mg in 5 mL of 0.1 N hydrochloric acid, and add about 50 mg of
stannous chloride: a curdy tan-orange precipitate is formed.
Tests
Residue on ignition: not more than 1.0 mg, from 10.0 g (0.01%).
Insoluble matter: Dissolve 1 g in 5 mL of water: it dissolves completely and
the solution is clear.
Selenate and sulfate: Dissolve about 0.5 g in 10 mL of water, add 0.1 mL of
hydrochloric acid and 1 mL of barium chloride, and mix: no turbidity or precipitate
is formed in 10 minutes.
