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H 2 AsO − 4 + H 2 O ⇌ HAsO 2− 4 + [H 3 O] +, pK a2 = 6.94 HAsO 2− 4 + H 2 O ⇌ AsO 3− 4 + [H 3 O] +, pK a3 = 11.5. These pK a values are close to those for phosphoric acid. The highly basic arsenate ion (AsO 3− 4) is the product of the third ionization. Unlike phosphoric acid, arsenic acid is an oxidizer, as illustrated by its ...
In its standard state arsine is a colorless, denser-than-air gas that is slightly soluble in water (2% at 20 °C) [1] and in many organic solvents as well. [citation needed] Arsine itself is odorless, [5] but it oxidizes in air and this creates a slight garlic or fish-like scent when the compound is present above 0.5 ppm. [6]
Cacodylic acid is highly toxic by ingestion, inhalation, or skin contact.The U.S. EPA states that all forms of arsenic are a serious risk to human health and the United States Agency for Toxic Substances and Disease Registry ranked arsenic as number 1 in its 2001 Priority List of Hazardous Substances at Superfund sites. [9]
The biogeochemistry of arsenic is complex and includes various adsorption and desorption processes. The toxicity of arsenic is connected to its solubility and is affected by pH. Arsenite (AsO 3− 3) is more soluble than arsenate (AsO 3− 4) and is more toxic; however, at a lower pH, arsenate becomes more mobile and toxic. It was found that ...
Trihydrogen arsenate is also known as arsenic acid. At a given pH, the distribution of these arsenate species can be determined from their respective acid dissociation constants. [17] H 3 AsO 4 + H 2 O ⇌ H 2 AsO − 4 + [H 3 O] + (pK a1 = 2.19) H 2 AsO − 4 + H 2 O ⇌ HAsO 2− 4 + [H 3 O] + (pK a2 = 6.94) HAsO 2− 4 + H 2 O ⇌ AsO 3− 4 ...
Arsenic forms colorless, odorless, crystalline oxides As 2 O 3 ("white arsenic") and As 2 O 5 which are hygroscopic and readily soluble in water to form acidic solutions. Arsenic(V) acid is a weak acid and the salts are called arsenates , [ 5 ] the most common arsenic contamination of groundwater , and a problem that affects many people.
In gastroenterology, esophageal pH monitoring is the current gold standard for diagnosis of gastroesophageal reflux disease (GERD). It provides direct physiologic measurement of acid in the esophagus and is the most objective method to document reflux disease, assess the severity of the disease and monitor the response of the disease to medical or surgical treatment.
Arsenic-arsenic bonds are very weak, and oligomeric arsenic compounds are even more liable to oxidize than their hydrogenated precursors. [6]: 318–320 The following reaction can, however, be prepared through electrochemical reduction in a zinc-sulfate cell. [6]: 473 Oxidation first forms polymeric arsinoxides, e.g.: MeAs + O → MeAsO