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Arsenic acid

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Identification
Molecular formula
H3AsO4
CAS number
7778-39-4
IUPAC name
arsoric acid
State
State

At room temperature, arsenic acid is typically a solid in its crystalline form, but it can readily exist as a viscous liquid if moisture is absorbed from the air due to its hygroscopic nature.

Melting point (Celsius)
35.50
Melting point (Kelvin)
308.65
Boiling point (Celsius)
120.00
Boiling point (Kelvin)
393.15
General information
Molecular weight
141.94g/mol
Molar mass
141.9430g/mol
Density
2.5000g/cm3
Appearence

Arsenic acid appears as a white, crystalline solid. It is hygroscopic, meaning it is capable of absorbing moisture from the air. Often, it can form a viscous, syrupy liquid due to its affinity for water.

Comment on solubility

Solubility of Arsenic Acid (H3AsO4)

Arsenic acid, or H3AsO4, is known for its solubility characteristics in various solvents. Here are some key points to consider:

  • Water Solubility: Arsenic acid is highly soluble in water, making it a useful compound in aqueous solutions.
  • Concentration: The solubility of H3AsO4 increases with higher temperatures, demonstrating an endothermic behavior.
  • pH Dependence: It forms anionic species in solution, particularly in acidic conditions, contributing to further solubility in lower pH environments.
  • Organic Solvent Solubility: H3AsO4 is generally less soluble in organic solvents compared to water, which limits its use in non-aqueous chemistry.

In summary, the solubility of arsenic acid is significant in water, particularly under specific conditions. As noted, "Its behavior in solution is greatly influenced by both temperature and pH." Understanding these factors can be crucial for applications in chemical synthesis and analysis.

Interesting facts

Interesting Facts about Arsenic Acid

Arsenic acid, known scientifically as H3AsO4, is a fascinating compound that has garnered attention in both historical and contemporary chemistry. Here are some compelling insights about this compound:

  • Historical Significance: Arsenic acid has been studied since the 18th century and is one of several oxoacids of arsenic. Its discovery played a role in understanding arsenic chemistry, which was crucial due to the element's toxicological implications.
  • Chemical Properties: As a triprotic acid, arsenic acid can donate three protons (H+) in solution, making it a strong acid. Its chemistry is critical for various applications, especially in the field of analytical chemistry.
  • Applications: Arsenic acid finds its use in the synthesis of various arsenic compounds, which are important in manufacturing glass, ceramics, and semiconductors. It also plays a role in pesticide formulations and wood preservative products.
  • Toxicity: Despite its utility, arsenic compounds are widely known for their toxicity. Arsenic acid itself can pose significant health risks, including developmental and carcinogenic effects, which necessitates careful handling.
  • Environmental Impact: Arsenic acid can be present in some industrial waste, posing risks to groundwater and aquatic ecosystems. The monitoring and remediation of arsenic contamination in the environment remain a critical area of research.
  • Anecdotal Uses: Historically, arsenic trioxide, related to arsenic acid, was infamously utilized in poisonings and has been referenced in various literature as a "silent killer" due to its flavorless and odorless properties.

In conclusion, while arsenic acid may seem like a simple compound, its implications in chemical science, environmental issues, and historical contexts reveal a rich tapestry of significance. As we continue to explore its properties, the balance of its applications and toxicity remains a pivotal focus for scientists and policymakers alike.

Synonyms
Arsenic acid
arsoric acid
Orthoarsenic acid
7778-39-4
Zotox
Desiccant L-10
Scorch
Arsenic acid (H3AsO4)
Crab grass killer
Dessicant L-10
Arsenic acid, liquid
Caswell No. 056
Zotox Crab Grass Killer
RCRA waste number P010
HI-Yield desiccant H-10
Acide arsenique liquide
HSDB 431
Acide arsenique liquide [French]
UNII-N7CIZ75ZPN
N7CIZ75ZPN
EINECS 231-901-9
tetraoxoarsenic acid
EPA Pesticide Chemical Code 006801
CHEBI:18231
trihydroxidooxidoarsenic
H3AsO4
ARSENIC ACID [MI]
trihydrogen tetraoxoarsenate
ARSENIC ACID [HSDB]
[AsO(OH)3]
ARSENIC ACID [WHO-DD]
DTXSID1034341
EC 231-901-9
(AsO(OH)3)
Arsenic acid H3AsO4
ACIDE ARSENIQUE LIQUIDE (FRENCH)
UN1553
UN1554
RCRA waste no. P010
Desiccant L10
Dessicant L10
8AR
Arsenic acid, solid
Caswell no 056
tetraoxidoarsenate(3-)
UN1553(liquid)
HIYield desiccant H10
UN1554(solid)
ARSENIC ACID SOLUTION
Pesticide Code: 006801
Lithium arsenate (Li3AsO4)
Monocesium arsenate, 2h-labeled
CHEMBL2374288
DTXCID9014341
NSC309956
Arsenic acid, solid [UN1554] [Poison]
Arsenic acid, liquid [UN1553] [Poison]
NS00080620
C01478
Q413334
231-901-9