Arsenic acid Formula

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The arsenic acid formula, also named as Orthoarsenic acid formula or Arsoric acid formula is discussed in this article. It is an arsenic oxoacid which consists of three hydroxy groups and one oxo group. They are attached to the central arsenic atom. The molecular or chemical formula of Arsenic acid is H3AsO4.

In its aqueous form, it is a colourless solution. In its crystalline form, it is white and translucent. It is hygroscopic and non-combustible. It functions as an Escherichia coli metabolite. It is the conjugate acid of an arsenate ion and an arsenate(1-).

Arsenic acid Formula Structure

Properties Of Arsenic acid Formula

Chemical formulaH3AsO4
Molecular weight 141.94 g/mol
Density 2.5 g/cm3
Boiling point 120 °C
Melting point 35.5 °C

Use Of Arsenic Acid 

  • It is occasionally used in wood preservatives.
  • It is used as a reagent in some dyes.
  • It is used as a finishing agent in metal and glass.

Safety Measures Of Arsenic Acid 

  • It is corrosive and highly toxic when ingested.
  • It is a human carcinogen and a threat to the environment and therefore immediate steps should be followed to limit the spread.


Arsenic acid is a chemical compound with the formula H3AsO4. It is an oxoacid of arsenic, and is a strong acid. It is a colorless, odorless, crystalline solid that is soluble in water.


Arsenic acid is used in a variety of industrial and agricultural applications, including as a preservative in wood, as a pesticide, and as a feed additive for livestock. It is also used in the production of glass, semiconductors, and other materials.


Arsenic acid is used in the food industry as a preservative and color enhancer. It is also used to prevent spoilage and to improve the flavor of certain foods.


Arsenic acid is not beneficial for health. In fact, it is a toxic chemical that can cause serious health problems if ingested.


Arsenic acid is a toxic chemical that can cause serious health problems if ingested or inhaled. Long-term exposure to arsenic acid can lead to cancer, skin lesions, and organ damage. In addition, it can cause neurological problems, such as headaches, confusion, and memory loss.


Arsenic acid is regulated across the world by various international organizations, such as the World Health Organization (WHO), the United Nations Environment Programme (UNEP), and the European Union (EU). These organizations have set limits on the amount of arsenic that can be present in drinking water, food, and other products. Additionally, many countries have their own regulations and standards for arsenic levels in their environment.

Preparation of arsenic acid

We can prepare arsenic acid by treating arsenic trioxide with concentrated nitric acid. As a byproduct, it produces dinitrogen trioxide.

As2O3+ 2 HNO3+ 2 H2O → 2 H3AsO4+ N2O3

After that, the resulting solution is cool down to give colorless crystal of the hemihydrate H3AsO4·1⁄2H2O. On the other hand, the dihydrate H3AsO4·2H2O produces when the crystallization occurs at lower temperatures.

Application of arsenic acid

Its commercial uses are limited due to its toxicity. Also, it is a precursor to a range of pesticides. Occasionally, we find its uses as a broad-spectrum biocide, as a wood preservative, a finishing agent for glass and metal, and a reagent in the synthesis of some dyestuffs and organic arsenic compounds.

Uses of arsenic acid

Historically, the agriculture industry uses arsenic acid in a variety of ways that include pesticides, insecticides, herbicides, cotton desiccants, soil sterilants, and defoliants, etc. In clothes, we use it as an anti-microbial. Also, the automobile industry uses them in manufacturing. We use it as a raw material in a variety of industries and products such as cosmetics, chemical manufacturing, production of metals, etc. Used as an agrochemical crop for growing. It is also an agent in glass manufacturing.

Arsenic Acid Side Effects

The following are the Arsenic Acid side effects:

  • Acute Arsenic Side poisoning can cause vomiting, abdominal pain, and diarrhea.
  • It can cause muscle cramping and, if consumed in higher concentrations, can cause death.
  • It can cause chills and irregular fever.
  • It can cause abdominal pain and high blood pressure problems.

Solved example for you

Question: Mention a method to prepare arsenic acid?

Solution: We can directly prepare arsenic acid from its elemental arsenic form by moistening and treating it with ozone (O3) and water (3 H2O):

2 As + 3 H2O + 5 O3 → 2 H3AsO4 + 5 O2

Arsenic Acid Formula FAQs

Is Arsenic acid a strong acid?

Arsenic acid is a weak acid.

What is Arsenic acid used for?

It is generally used as a wood preservative, biocide, insecticide and synthesis of organic compounds.

.Is Arsenic soluble in water?

The compound of Arsenic acid is soluble in water.

Does Arsenic acid react with hydrochloric acid?

Arsenic acid reacts with Hydrochloric acid to form Arsenic Sulphide.

Is Arsenic acid highly reactive?

Arsenic acid is highly reactive and is a compound of a weak acid.

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