Alkali hydroxide
Encyclopedia
The alkali hydroxides are a class of chemical compound
s which are composed of an alkali metal
cation and the hydroxide
anion (HO-). The alkali hydroxides are:
"A strong base completely ionizes in aqueous solution to give HO- and a cation. Sodium hydroxide is an example of a strong base. The principal strong bases are the hydroxides of Group IA elements and group IIA elements."
The most common alkali hydroxide is sodium hydroxide, which is readily available in most hardware stores in products such as a drain cleaners. Another common alkali hydroxide is potassium hydroxide. This is available as a solution used for cleaning terraces and other areas made out of wood.
All alkali hydroxides are very corrosive, being strongly alkaline.
A typical school demonstration demonstrates what happens when a piece of an alkali metal is introduced to a bowl of water. A vigorous reaction occurs, producing hydrogen
gas and the specific alkali hydroxide. For example, if sodium is the alkali metal:
Chemical compound
A 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...
s which are composed of an alkali metal
Alkali metal
The alkali metals are a series of chemical elements in the periodic table. In the modern IUPAC nomenclature, the alkali metals comprise the group 1 elements, along with hydrogen. The alkali metals are lithium , sodium , potassium , rubidium , caesium , and francium...
cation and the hydroxide
Hydroxide
Hydroxide is a diatomic anion with chemical formula OH−. It consists of an oxygen and a hydrogen atom held together by a covalent bond, and carrying a negative electric charge. It is an important but usually minor constituent of water. It functions as a base, as a ligand, a nucleophile, and a...
anion (HO-). The alkali hydroxides are:
- Lithium hydroxideLithium hydroxideLithium hydroxide is an inorganic compound with the formula LiOH. It is a white hygroscopic crystalline material. It is soluble in water and slightly soluble in ethanol...
(LiOH) - Sodium hydroxide (NaOH)
- Potassium hydroxidePotassium hydroxidePotassium hydroxide is an inorganic compound with the formula KOH, commonly called caustic potash.Along with sodium hydroxide , this colorless solid is a prototypical strong base. It has many industrial and niche applications. Most applications exploit its reactivity toward acids and its corrosive...
(KOH) - Rubidium hydroxideRubidium hydroxideRubidium hydroxide is a strong basic chemical and alkali that is formed by one rubidium ion and one hydroxide ion.Rubidium hydroxide does not appear in nature. However it can be obtained by synthesis from rubidium oxide...
(RbOH) - Caesium hydroxideCaesium hydroxideCaesium hydroxide is a chemical compound consisting of an atom of caesium and a hydroxide group . It is a powerful base, much like other alkali metal hydroxides such as sodium hydroxide and potassium hydroxide...
(CsOH)
"A strong base completely ionizes in aqueous solution to give HO- and a cation. Sodium hydroxide is an example of a strong base. The principal strong bases are the hydroxides of Group IA elements and group IIA elements."
The most common alkali hydroxide is sodium hydroxide, which is readily available in most hardware stores in products such as a drain cleaners. Another common alkali hydroxide is potassium hydroxide. This is available as a solution used for cleaning terraces and other areas made out of wood.
All alkali hydroxides are very corrosive, being strongly alkaline.
A typical school demonstration demonstrates what happens when a piece of an alkali metal is introduced to a bowl of water. A vigorous reaction occurs, producing hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
gas and the specific alkali hydroxide. For example, if sodium is the alkali metal:
- Sodium + water → sodium hydroxide + hydrogen gas
- 2 Na + 2 H2O → 2 NaOH + H2