Basic oxides are that show basic properties, in opposition to . A basic oxide can either react with water to form a base, or with an acid to form a salt and water in a neutralization reaction.
Examples include:
Definition
An oxide is a chemical compound in which one or more oxygen atoms combined with another element, such as H
2O or CO
2. Based on their acid-base characteristics, oxides can be classified into four categories: acidic oxides, basic oxides, and
amphoteric oxides and neutral oxides.
A basic oxide, also called a base anhydride (meaning "base without water"), is usually formed in the reaction of oxygen with metals, especially alkali metals (group 1) and alkaline earth (group 2) metals. Both of these groups form Ionic compound oxides that dissolve in water to form basic solutions of the corresponding metal hydroxide:
Alkali metals (Group 1)
- X2O + H2O → 2XOH (X = group 1 element)
Alkaline earth metals (group 2)
- XO + H2O → X(OH)2 (X = group 2 element)
For example, the basic oxide Lithium oxide becomes the hydroxide LiOH, and Barium oxide becomes Barium hydroxide after reacting with water. In contrast, non-metals usually form . In general, the basicity of oxides increases when towards the lower-left corner of the periodic table, which corresponds to increased metallic properties.
Examples
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All oxides of group 1 & 2 elements are basic (except BeO), they react with water to form a base:
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Some oxides of other main group elements are basic, reacting with water to form a base:
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Thallium(I) oxide, a group 13 oxide, reacts with water to produce thallium(I) hydroxide: Tl2O + H2O → 2 TlOH
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Bismuth(III) oxide, a group 15 oxide, reacts with water to produce bismuth(III) hydroxide: Bi2O3 + 3H2O → 2 Bi(OH)3
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In neutralization reactions, basic oxides reacts with an acid to form salt and water:
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Magnesium oxide reacts with hydrogen chloride (acid) to produce magnesium chloride (salt) and water: MgO + 2 HCl → MgCl2 + H2O
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Sodium oxide reacts with hydrogen chloride (acid) to produce sodium chloride (salt) and water: Na2O + 2 HCl → 2 NaCl + H2O
See also
