Iodic acid, HIO
3, can be obtained as a white solid. It dissolves in water very well, but it also exists in the pure state, as opposed to
chloric acidChloric acid, HClO3, is an oxoacid of chlorine, and the formal precursor of chlorate salts. It is a strong acid and oxidizing agent....
or
bromic acidBromic acid, HBrO3, is a bromine oxoacid. Its salts, the bromates, are powerful oxidizing agents in the solid state, much like the chlorates, and are used in specialty pyrotechnical mixtures. Bromic acid is a key reagent in the Belousov-Zhabotinsky oscillating reaction. Bromic acid is...
. Iodic acid contains iodine in the oxidation state +5 and it is one of the most stable oxo-acids of the halogens in its pure state. When iodic acid is carefully heated, it dehydrates to
iodine pentoxideIodine pentoxide is the chemical compound with the formula I2O5. This iodine oxide is the anhydride of iodic acid. It is produced by dehydrating iodic acid at 200 °C in a stream of dry air:- Structure :...
. On subsequent heating, the iodine pentoxide further decomposes, giving a mix of iodine, oxygen and lower oxides of iodine.
Iodic acid can be produced by oxidizing I
2 with
chlorineChlorine Chlorine Chlorine ( , from the Greek word 'χλωρóς' (khlôros, meaning 'pale green'), is the chemical element with atomic number 17 and symbol Cl. It is a halogen, found in the periodic table in group 17 (formerly VII, VIIa, or VIIb). As the chloride ion, which is part of common salt and...
in an aqueous solution.
Iodic acid is a relatively
strong acidA strong acid is an acid that dissociates completely in an aqueous solution , or in other terms, with a pKa < −1.74. This generally means that in aqueous solution at standard temperature and pressure, the concentration of hydronium ions is equal to the concentration of strong acid...
with a
pKaAn acid dissociation constant, Ka, is a quantitative measure of the strength of an acid in solution. It is the equilibrium constant for a chemical reaction known as dissociation in the context of acid-base reactions...
of 0.75.
Iodic acid, HIO
3, can be obtained as a white solid. It dissolves in water very well, but it also exists in the pure state, as opposed to
chloric acidChloric acid, HClO3, is an oxoacid of chlorine, and the formal precursor of chlorate salts. It is a strong acid and oxidizing agent....
or
bromic acidBromic acid, HBrO3, is a bromine oxoacid. Its salts, the bromates, are powerful oxidizing agents in the solid state, much like the chlorates, and are used in specialty pyrotechnical mixtures. Bromic acid is a key reagent in the Belousov-Zhabotinsky oscillating reaction. Bromic acid is...
. Iodic acid contains iodine in the oxidation state +5 and it is one of the most stable oxo-acids of the halogens in its pure state. When iodic acid is carefully heated, it dehydrates to
iodine pentoxideIodine pentoxide is the chemical compound with the formula I2O5. This iodine oxide is the anhydride of iodic acid. It is produced by dehydrating iodic acid at 200 °C in a stream of dry air:- Structure :...
. On subsequent heating, the iodine pentoxide further decomposes, giving a mix of iodine, oxygen and lower oxides of iodine.
Preparation
Iodic acid can be produced by oxidizing I
2 with
chlorineChlorine Chlorine Chlorine ( , from the Greek word 'χλωρóς' (khlôros, meaning 'pale green'), is the chemical element with atomic number 17 and symbol Cl. It is a halogen, found in the periodic table in group 17 (formerly VII, VIIa, or VIIb). As the chloride ion, which is part of common salt and...
in an aqueous solution.
Properties
Iodic acid is a relatively
strong acidA strong acid is an acid that dissociates completely in an aqueous solution , or in other terms, with a pKa < −1.74. This generally means that in aqueous solution at standard temperature and pressure, the concentration of hydronium ions is equal to the concentration of strong acid...
with a
pKaAn acid dissociation constant, Ka, is a quantitative measure of the strength of an acid in solution. It is the equilibrium constant for a chemical reaction known as dissociation in the context of acid-base reactions...
of 0.75. It is strongly oxidizing in acidic solution, less so in basic solution. When iodic acid acts as oxidizer, then the product of the reaction is either iodine, or iodide ion. Under some special conditions (very low pH and high concentration of chloride ion, e.g. in concentrated hydrochloric acid), iodic acid is reduced to iodine trichloride, a golden yellow compound in solution and no further reduction occurs. In the absence of chloride ions, when there is an excess amount of reductor, then all
iodateAn iodate is a conjugate base of iodic acid. In the iodate anion, iodine is bonded to three oxygen atoms and the molecular formula is IO3−. The molecular geometry of iodate is trigonal pyramid....
is converted to iodide ion. When there is an excess amount of iodate, then part of the iodate is converted to iodine.
Uses
Iodic acid is used as a
strong acidA strong acid is an acid that dissociates completely in an aqueous solution , or in other terms, with a pKa < −1.74. This generally means that in aqueous solution at standard temperature and pressure, the concentration of hydronium ions is equal to the concentration of strong acid...
in
analytical chemistryAnalytical chemistry is the study of the chemical composition of natural and artificial materials. Properties studied in analytical chemistry include geometric features such as molecular morphologies and distributions of species, as well as features such as composition and species identity...
. It may be used to standardize solutions of both
weakIn chemistry, a weak base is a chemical base that does not ionize fully in an aqueous solution. As Bronsted-Lowry bases are proton acceptors, a weak base may also be defined as a chemical base in which protonation is incomplete. This results in a relatively low pH level compared to strong bases...
and strong bases, with
methyl redMethyl red, also called C.I. Acid Red 2, is an indicator dye that turns red in acidic solutions. It is an azo dye, and is a dark red crystalline powder....
or
methyl orangeMethyl orange is a pH indicator frequently used in titrations.It is often chosen to be used in titrations because of its clear colour change. Because it changes colour at the pH of a mid-strength acid, it is usually used in titrations for acids...
as the
indicatorA pH indicator is a halochromic chemical compound that is added in small amounts to a solution so that the pH of the solution can be determined visually. Hence a pH indicator is a chemical detector for hydronium ions...
.
Use in salt industry
Iodic acid can be used to synthesize
Sodium iodateSodium iodate is a chemical compound. Sodium iodate is an oxidizing agent and as such it can cause fires upon contact with combustible materials or reducing agents.-Preparation:...
or
Potassium iodatePotassium iodate is a chemical compound. It is sometimes used in radiation treatment, as it can replace radioactive iodine from the thyroid.-Chemical properties:...
for increasing
iodineIodine , is a chemical element that has the symbol I and atomic number 53. Naturally-occurring iodine is a single isotope with 74 neutrons....
content of salt.