arsenious acid

arsenious acid

[är′sēn·ē·əs ′as·əd]
(inorganic chemistry)
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Arsenic in aqueous solution can be found in oxidation condition state; As (III) as arsenious acid HAsO2 in reductor conditions until pH= 9 and As (V) as arsenic acid H3AsO4 at pH As (III) >As (V) >DMA (V) >MMA (V) [14].
Oxidation of several other reducing agents including oxalate, thiosulphate, Ce (IV), ammonia, ammonium ion, arsenious acid and hydrogen peroxide (House, 1962; Wilmarth and Haim, 1962) by peroxodisulphate in presence of [Ag.sup.+] ion have also been investigated and it was found that the kinetic order is first for both [S.sub.2][O.sup.2-.sub.8] and [Ag.sup.+] but zero in reductant.
After we added 60 [micro],L of arsenious acid and incubated the mixture at room temperature for 10 min, we monitored the absorbance at 405 nm ([A.sub.405nm])in the absence of eerie ammonium sulfate.
Izumi Nakai, professor of analytical chemistry at the Science University of Tokyo, conducted a test with an advanced instrument called the Spring Eight, which he said showed that arsenious acid found in the defendant's house is the same as the poison in the curry.
Masumi is accused of putting arsenious acid, one of the most toxic types of arsenic, into curry that was served at the July 25 festival in the Sonobe district of Wakayama, western Japan.
Many methods for assessing urinary iodine exist (3-8), most based on the Sandell-Kolthoff reaction (9), in which iodide catalyzes the reduction of ceric ammonium sulfate (yellow) to the colorless cerous form in the presence of arsenious acid. Although iodide is the chemical form for both the catalytic reaction and in urine, some preliminary treatment is needed to rid urine of impurities, most commonly by acid digestion (3, 5).
(c) Arsenious acid solution: 10 g of [As.sub.2][O.sub.3], 50 g of NaCl, 400 mL of 2.5 mol/L [H.sub.2]S[O.sub.4], and 600 mL water; heated gently to dissolve, diluted to a final volume of 2 L, filtered, and stored in a dark bottle away from light at 20-30 [degrees]C (stable for at least 6 months)
Masumi is accused of putting arsenious acid, one of the most toxic types of arsenic, into the curry that was served at the summer festival in the Sonobe district of Wakayama, western Japan.
Arsenious acid solution (100 [micro]L) was added to the wells and mixed; 50 [micro]L of ceric ammonium sulfate solution was then added quickly (within 1 min), using a multichannel pipette (Finnpipette Varichannel; Labsystems).
After the test tubes were cooled, 3.5 mL of arsenious acid solution was added into each tube and mixed.
6 -- Police announce arsenic used to poison curry contained either arsenious acid or an arsenious acid compound.
One commonly used method, their "Method A," is based on an initial mild chloric acid digestion to remove interfering substances, after which the iodine is quantified by its catalytic effect on reducing yellow ceric ion to colorless cerous ion in the presence of arsenious acid (Sandell-Kolthoff reaction).