Arsenic acid
- русский язык имя
- английское имяArsenic acid
- CAS №1327-52-2
- CBNumberCB62130237
- ФормулаAsH3O4
- мольный вес141.94
- файл Mol1327-52-2.mol
химическое свойство
| РН | 3.08(1 mM solution);2.31(10 mM solution);1.7(100 mM solution) |
| FDA UNII | N7CIZ75ZPN |
| Пестициды Закон о свободе информации (FOIA) | Arsenic acid |
| РИДАДР | UN 1553 6.1/ PGI |
| РИДАДР | UN 1554 6.1/ PGII |
| Класс опасности | 6.1 |
| Группа упаковки | I |
| Группа упаковки | II |
| Токсичность | chicken,LDLo,oral,125mg/kg (125mg/kg),"Ueber die Wirkung Verschiedener Gifte Auf Vogel, Dissertation," Forchheimer, L., Pharmakologischen Institut der Universitat Wurzburg, Fed. Rep. Ger., 1931Vol. -, Pg. -, 1931. |
Arsenic acid химические свойства, назначение, производство
Описание
Arsenic acid has the molecular formula H3AsO4. More descriptively written as AsO(OH)3, this colorless acid is the arsenic analog of phosphoric acid. Arsenate and phosphate salts behave very similarly. Arsenic acid as such has not been isolated, but only found in solution where it is largely ionized. Its hemihydrate form (H3AsO4·1/2H2O) does form stable crystals. Crystalline samples dehydrate with condensation at 100 °C.Arsenic acid is a tetrahedral species of idealized symmetry C3v with As—O bonds lengths ranging from 1.66 to 1.71? . Being a triprotic acid, its acidity is described by three equilibria:
H3AsO4 ? H2AsO4- + H+ (pk1 =10-2.19)
H2AsO4 ? 5HasO4 2- + H+ (pk2 = 10-6.94)
HasO4 2 ? 5AsO4 3- + H+ (pk3 = 10-11.5)
Подготовка
Arsenic acid is prepared by treating arsenic trioxide with concentrated nitric acid or by combination of arsenic acid with water. The latter reaction is very slow. It is also formed when metaarsenic or pyroarsenic acid is treated with cold water.