Write the chemical formula for sulfurous acid, formula:
The Correct Answer and Explanation is:
The correct chemical formula for sulfurous acid is H₂SO₃.
Explanation:
Sulfurous acid is a weak inorganic acid composed of hydrogen, sulfur, and oxygen. It is formed when sulfur dioxide (SO₂) dissolves in water, leading to the equilibrium reaction:
SO2+H2O↔H2SO3SO₂ + H₂O \leftrightarrow H₂SO₃
This acid exists only in aqueous solutions and is not typically isolated as a pure compound. It is unstable, meaning it readily decomposes back into sulfur dioxide and water when left standing.
Structure and Properties
Sulfurous acid consists of a sulfur atom bonded to three oxygen atoms, with two hydrogen atoms contributing to its acidic nature. The oxidation state of sulfur in this compound is +4, which is lower than that in sulfuric acid (H₂SO₄), where sulfur has an oxidation state of +6. This difference makes sulfurous acid less oxidizing than sulfuric acid.
Sulfurous acid is considered a diprotic acid because it has two hydrogen atoms that can dissociate in solution, leading to the formation of bisulfite (HSO₃⁻) and sulfite (SO₃²⁻) ions.
Applications and Significance
Sulfurous acid is used industrially as a mild reducing agent and is involved in chemical processes such as bleaching and disinfecting. In food preservation, compounds derived from sulfurous acid, such as sulfites, help prevent oxidation and spoilage of certain products.
Environmental significance arises from its role in acid rain formation. When SO₂ dissolves in atmospheric moisture, sulfurous acid forms and later oxidizes to sulfuric acid, contributing to acid precipitation that affects ecosystems and buildings.
Understanding sulfurous acid’s formula and behavior is essential for studies in chemistry, environmental science, and industrial application
