Chlorous acid
Chlorous acid is an unstable chlorine oxoacid with the formula HClO₂, in which chlorine has oxidation state +3. Its salts are called chlorites.
Chlorite: A chlorite is a salt or ester containing the chlorite ion, ClO₂⁻. Chlorous acid loses a proton to form the chlorite ion.
Chlorine: A halogen chemical element with atomic number 17. Chlorous acid is built from chlorine, oxygen, and hydrogen.
Chlorine dioxide: A reactive chlorine oxide, ClO₂, used as a disinfectant and bleaching agent. Acidification of chlorite can generate chlorine dioxide, a major practical connection to HClO₂ chemistry.
Chlorous acid versus chloric acid: A comparison of HClO₂ and HClO₃, chlorine oxoacids with oxidation states +3 and +5. The names differ by one syllable while their formulas and oxidation states differ substantially.
Chlorine disproportionation: A redox reaction in which chlorine in one oxidation state forms products with higher and lower oxidation states. Chlorous acid can disproportionate, producing chlorine compounds with different oxidation states.
Oxoacid: An acid containing oxygen bonded to a central element, typically with ionizable hydrogen. Chlorous acid belongs to the family of oxygen-containing acids.
Sodium chlorite: An ionic compound, NaClO₂, that supplies chlorite ions in solution. Its acidified solutions are used to produce chlorine dioxide.
Chlorite–chlorate equilibrium: The relationship between chlorite, ClO₂⁻, and chlorate, ClO₃⁻, under chemical oxidation or reduction. Chlorite is the conjugate base of chlorous acid; chlorate belongs to the higher oxidation state series.
Oxidation state: A formal charge assigned to an atom by treating its bonds as ionic. The +3 oxidation state identifies chlorous acid within chlorine’s oxoacid series.
Hypochlorous acid: A chlorine oxoacid with formula HClO and chlorine in oxidation state +1. It has fewer oxygen atoms and a lower chlorine oxidation state than chlorous acid.