ARSENIC ACID
![ARSENIC ACID Structure](CAS/20180808/GIF/7778-39-4.gif)
- CAS No.
- 7778-39-4
- Chemical Name:
- ARSENIC ACID
- Synonyms
- zotox;scorch;ARSENATE;Arsensure;orthoarsenic;caswellno056;dessicantl-10;desiccantl-10;orthoarsenate;crabgrasskiller
- CBNumber:
- CB1481761
- Molecular Formula:
- AsH3O4
- Molecular Weight:
- 141.94
- MOL File:
- 7778-39-4.mol
- Modify Date:
- 2024/8/28 13:53:21
Melting point | 35.5℃ [HAW93] |
---|---|
Boiling point | 160℃[at 101 325 Pa] |
Density | 2.5 [CRC10] |
vapor pressure | 18.45hPa at 25℃ |
solubility | very soluble in H2O, ethanol |
form | exists only in solution |
pka | 3.09±0.10(Predicted) |
color | exists only in solution |
PH | pKa1= 2.31, pKa2 = 7.05, pKa3 = 11.9(25℃) |
Water Solubility | very soluble H2O, EtOH [CRC10] |
Stability | Incompatible with metals. |
CAS DataBase Reference | 7778-39-4(CAS DataBase Reference) |
EPA Substance Registry System | Arsenic acid (7778-39-4) |
SAFETY
Risk and Safety Statements
Symbol(GHS) | ![]() ![]() ![]() GHS08,GHS09,GHS06 |
---|---|
Signal word | Danger |
Hazard statements | H331-H350-H301-H410-H400 |
Precautionary statements | P261-P271-P304+P340-P311-P321-P403+P233-P405-P501-P273-P391-P501-P264-P270-P301+P310-P321-P330-P405-P501-P273-P391-P501 |
RIDADR | 1554 |
HazardClass | 6.1(a) |
PackingGroup | II |
ARSENIC ACID Chemical Properties,Uses,Production
Chemical Properties
Arsenic acid is a clear, white, semi-transparent crystal (sugar or sand-like) material. Arsenic acid is one of the most commercially important pentavalent compounds of arsenic. It is used for wood treatment/wood preservative, as a drying agent, a soil sterilant, and to make other arsenates. It is a broad-spectrum biocide, a fi nishing agent for glass and metal, and a reagent in the retard of dyestuffs and organic arsenic compounds. Arsenic acid decomposes on heating, producing toxic and corrosive fumes. It is a strong oxidant and reacts with combustible and reducing materials and attacks/ damages metals to produce toxic and flammable arsine. It is soluble in water and forms the arsenate ion.
Physical properties
Hygroscopic translucent crystals; density between 2 to 2.5 g/cm3; melts at 35.5°C; loses water when heated to 160°C; highly soluble in cold water; soluble in alcohol, glycerol and alkalies.
Uses
Pesticides; herbicides; fungicides; algicides.
Preparation
Arsenic acid is prepared by treating arsenic trioxide with concentrated nitric acid; or by combination of arsenic pentoxide with water. The latter reaction is very slow. It is also formed when meta- or pyroarsenic acid is treated with cold water.
Definition
Any salt or ester of arsenic acid. They are distributed widely in nature and contaminate coal and metal ores. Arsenates uncouple oxidative phosphorylation by replacing inorganic phosphorous in the ATP.
General Description
White crystals. Melting point 95°F. Excessive drying produces As2O5.5/3H2O.
Air & Water Reactions
Hygroscopic. Water soluble.
Reactivity Profile
ARSENIC ACID may evolve very toxic gaseous arsine (AsH3) from contact with active metals, such as zinc and aluminum [Inorganic Chemicals Handbook, I, p. 175]. When heated to decomposition, ARSENIC ACID produces toxic fumes of metallic arsenic [Sax, 9th ed., p. 271]. The solution is weakly acidic and a weak oxidizing agent. Reacts with alkalis to generate some heat and precipitate arsenates.
Hazard
Carcinogen; toxic.
Health Hazard
Arsenic acid is absorbed into the body by inhalation of its vapor, through the skin, and by ingestion. Arsenic acid is an eye irritant and may cause burns. Most injuries result from exposure to dusts, causing conjunctivitis, lacrimation, photophobia, and chemosis. Exposures to arsenic acid cause poisoning with symptoms of irritation of the eyes, the skin, the respiratory tract, respiratory distress, sore throat, nausea, vomiting, diarrhea, poor appetite, and stomach cramps. Arsenic acid also causes effects on the blood, cardiovascular system, gastrointestinal tract, liver, and peripheral nervous system, leading to polyneuropathy and convulsions. Repeated exposures to high concentrations of arsenic acid have been reported to cause nerve damage, with “pins and needles,” numbness, and weakness of the arms and legs, and even death. Tachycardia is frequently reported following ingestion of arsenic acid salts and is contributed to by anxiety, intravascular fl uid depletion, and possibly direct arsenic-induced cardiotoxicity.
Fire Hazard
Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes. Some are oxidizers and may ignite combustibles (wood, paper, oil, clothing, etc.). Contact with metals may evolve flammable hydrogen gas. Containers may explode when heated.
Safety Profile
Confirmed human carcinogen. Poison by ingestion. An experimental teratogen. Human mutation data reported. When heated to decomposition it emits toxic fumes of arsenic. See also ARSENIC COMPOUNDS.
storage
Arsenic acid should be kept stored in an area without drain or sewer access. It should be separated from strong oxidants, strong bases, metals, strong reducing agents, food, and feedstuffs. Occupational workers should keep arsenic acid in a cool, well-ventilated area, away from heat. Workers should avoid storing or transporting arsenic acid with aluminium, copper, iron, or zinc.
Precautions
Occupational workers should be extremely careful and cautious during handling and use of arsenic acid.
ARSENIC ACID Preparation Products And Raw materials
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