Base anhydride
A base anhydride is an oxide of a chemical element from group 1 or 2 (the alkali metals and alkaline earth metals, respectively). They are obtained by removing water from the corresponding hydroxide base. If water is added to a base anhydride, a corresponding hydroxide salt can be re-formed.
Base anhydrides are not Brønsted–Lowry bases because they are not proton acceptors. However, they are Lewis bases, because they will share an electron pair with some Lewis acids, most notably acidic oxides.[1] They are potent alkalis and will produce alkali burns on skin, because their affinity for water (that is, their affinity for being slaked) makes them react with body water. For example, quicklime (calcium oxide) reacts with skin to become hydrated lime (calcium hydroxide), which is a strong base, chemically akin to lye.
Examples
Group 1 oxides
- Lithium oxide, which reacts with water forming lithium hydroxide
- Sodium oxide, which reacts with water forming sodium hydroxide
- Potassium oxide, which reacts with water forming potassium hydroxide
- Rubidium oxide, which reacts with water forming rubidium hydroxide
- Caesium oxide, which reacts with water forming caesium hydroxide
- Francium oxide, which reacts with water forming francium hydroxide
Group 2 oxides
- Magnesium oxide, which reacts with water forming magnesium hydroxide
- Calcium oxide, which reacts with water forming calcium hydroxide
- Strontium oxide, which reacts with water forming strontium hydroxide
- Barium oxide, which reacts with water forming barium hydroxide
- Radium oxide, which reacts with water forming radium hydroxide
Other
- Thallium oxide, which reacts with water forming thallium hydroxide
See also
References
- Principles of Modern Chemistry, 7th Edition. David Oxtoby, H. P. Gillis, Alan Campion. Published by Cengage Learning. Page 675-676. ISBN 978-0840049315