Alkalis
As alkalis (from Latin sal alkali from arab.القلية / al-qalya / ' potash '; Soda or sodium carbonate ) are substances that form alkaline solutions (lyes) with water . This not clearly defined group of substances includes, in particular, the oxides and hydroxides of the alkali and alkaline earth metals . Alkalis belong to the group of bases .
Alkalis are characterized by
- their solubility in water
- their corrosive, i.e. their aqueous solutions that have a destructive effect on plant and animal substances
- their peculiar pungent taste
- their ability to absorb carbon dioxide from the air , e.g. B. Soda lime
- their ability to combine with acids to form salts
- their property of forming soaps and glycerine with fats and fatty oils : saponification
- Alkalis give reddish, damp litmus paper a bluish tinge .
- Alkalis form hydroxide ions (OH - ) in solutions .