Express your answer as a chemical formula. Identify the phase in your answer.
The Correct Answer and Explanation is:
The correct chemical formula for sulfurous acid, including its phase, is:
H₂SO₃(aq)
Explanation:
Sulfurous acid is a weak inorganic acid with the molecular formula H₂SO₃. It consists of two hydrogen (H) atoms, one sulfur (S) atom, and three oxygen (O) atoms. It forms when sulfur dioxide (SO₂) dissolves in water, leading to partial ionization in aqueous solution. Unlike strong acids such as hydrochloric acid (HCl) or sulfuric acid (H₂SO₄), sulfurous acid does not fully dissociate in water.
The presence of (aq) in the chemical formula indicates that sulfurous acid exists in aqueous solution. This phase notation is essential in chemical reactions to distinguish substances that are dissolved in water. The phase of a substance can be solid (s), liquid (l), gas (g), or aqueous (aq), depending on its physical state under given conditions.
In solution, sulfurous acid undergoes partial dissociation, yielding hydrogen ions (H⁺) and bisulfite ions (HSO₃⁻). This ionization plays a role in the acid’s chemical behavior, especially in redox reactions and equilibrium processes. Since sulfurous acid is unstable in its pure form and does not exist as an isolated compound, it is commonly encountered in aqueous solution rather than as a gas or solid.
This acid is relevant in environmental chemistry, particularly in acid rain formation and industrial processes such as bleaching and water treatment. Understanding its aqueous nature helps in predicting its reactivity and interactions with other substances in solution. Proper identification of the phase ensures accurate representation of its behavior in reactions and chemical equations.
