Chlorous acid is a
chemical compoundA chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
with the formula HClO
2. It is a
weak acidA weak acid is an acid that dissociates incompletely and does not release all of its hydrogens in a solution i.e it does not completely donate all of its protons. These acids have higher pKa compared to strong acids, which release all of their hydrogens when dissolved in water.While strong acids...
. Chlorine possesses
oxidation stateIn chemistry, the oxidation state is an indicator of the degree of oxidation of an atom in a chemical compound. The formal oxidation state is the hypothetical charge that an atom would have if all bonds to atoms of different elements were 100% ionic. Oxidation states are typically represented by...
+3 in this acid. The pure substance is unstable, disproportionating to
hypochlorous acidHypochlorous acid is a weak acid with the chemical formula HClO. In the swimming pool industry, Hypochlorous acid is referred to as HOCl. It forms when chlorine dissolves in water. It cannot be isolated in pure form due to rapid equilibration with its precursor...
(Cl oxidation state +1) and
chloric acidChloric acid, HClO3, is an oxoacid of chlorine, and the formal precursor of chlorate salts. It is a strong acid and oxidizing agent....
(Cl oxidation state +5).
2HClO
2(aq) → HClO(aq) + HClO
3(aq)
ChloriteThe chlorite ion is ClO2−. A chlorite is a compound that contains this group,with chlorine in oxidation state +3...
salts such as
sodium chloriteSodium chlorite is a chemical compound used in the manufacture of paper.-Manufacture:The free acid, chlorous acid, HClO2, is only stable at low concentrations. Since it cannot be concentrated, it is not a commercial product. However, the corresponding sodium salt, sodium chlorite,...
are stable conjugate bases derived from this acid.
Chlorous acid is a
chemical compoundA chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
with the formula HClO
2. It is a
weak acidA weak acid is an acid that dissociates incompletely and does not release all of its hydrogens in a solution i.e it does not completely donate all of its protons. These acids have higher pKa compared to strong acids, which release all of their hydrogens when dissolved in water.While strong acids...
. Chlorine possesses
oxidation stateIn chemistry, the oxidation state is an indicator of the degree of oxidation of an atom in a chemical compound. The formal oxidation state is the hypothetical charge that an atom would have if all bonds to atoms of different elements were 100% ionic. Oxidation states are typically represented by...
+3 in this acid. The pure substance is unstable, disproportionating to
hypochlorous acidHypochlorous acid is a weak acid with the chemical formula HClO. In the swimming pool industry, Hypochlorous acid is referred to as HOCl. It forms when chlorine dissolves in water. It cannot be isolated in pure form due to rapid equilibration with its precursor...
(Cl oxidation state +1) and
chloric acidChloric acid, HClO3, is an oxoacid of chlorine, and the formal precursor of chlorate salts. It is a strong acid and oxidizing agent....
(Cl oxidation state +5).
2HClO
2(aq) → HClO(aq) + HClO
3(aq)
ChloriteThe chlorite ion is ClO2−. A chlorite is a compound that contains this group,with chlorine in oxidation state +3...
salts such as
sodium chloriteSodium chlorite is a chemical compound used in the manufacture of paper.-Manufacture:The free acid, chlorous acid, HClO2, is only stable at low concentrations. Since it cannot be concentrated, it is not a commercial product. However, the corresponding sodium salt, sodium chlorite,...
are stable conjugate bases derived from this acid. These salts are sometimes used in the production of chlorine dioxide.
Preparation
HClO
2 can be prepared through reaction of barium chlorite and dilute
sulfuric acidSulfuric acid, , is a strong mineral acid. It is soluble in water at all concentrations. Sulfuric acid has many applications, and is one of the top products of the chemical industry. World production in 2001 was 165 million tonnes, with an approximate value of US$8 billion...
:
- Ba(ClO2)2 + H2SO4 → BaSO4 + 2HClO2
Stability
Chlorine is the only one of the four
halogenThe halogens or halogen elements are a series of nonmetal elements from Group 17 IUPAC Style of the periodic table, comprising fluorine, ; chlorine, ; bromine, ; iodine, ; and astatine,...
s to form an isolable acid of formula HXO
2.
FluorineFluorine is the chemical element with atomic number 9, represented by the symbol F. Fluorine forms a single bond with itself in elemental form, resulting in the diatomic F
2 molecule. F
2 is a supremely reactive, poisonous, pale, yellowish brown gas. Elemental fluorine is the...
does not have the bonding capacity to do so, whereas the hypothetical bromous acid and iodous acid have never been isolated and only a few salts of
bromous acidBromous acid with the formula HBrO2 has bromine in the +3 oxidation state. The salts of bromous acid are called bromites. The acid is not stable and only occurs as an intermediate, for example in the oxidation of hypobromites.- Chemistry :...
, bromites, are known, and no iodites.