Base anhydride
A base anhydride is an oxide of a chemical element from group 1 or 2. 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 -formed.
Base anhydrides are Brønsted–Lowry bases because they are proton acceptors. In addition, they are Lewis bases, because they will share an electron pair with some Lewis acids, most notably acidic oxides. They are potent alkalis and will produce alkali burns on skin, because their affinity for water makes them react with body water.
Examples
- Quicklime is a base anhydride. It reacts with water to become hydrated lime, which is a strong base, chemically akin to lye. This reaction is exothermic.
- Sodium oxide is a very strong base that reacts readily and irreversibly with water to give sodium hydroxide: