User:Pumin Martin/sandbox

Basic oxides are oxides that show basic properties in opposition to acidic oxides and that either

• reacts with water to form a base; or
• reacts with an acid to form a salt and water which called [neutralization reactions].

They are usually formed by reacting oxygen with metals, especially alkali (+1 oxidation state) and alkaline earth metals (+2 oxidation state). Both of them are ionic oxide and can dissolve in water to form basic solutions of the metal hydroxide, whereas non-metals usually form acidic oxides. In general, basicity increases down at the left side (group 1A & 2A) of a periodic table.

Alkali Metals (Group 1A)

• X2O + H2O → 2XOH (X means group 1A)

Alkaline Earth Metals (Group 2A)

• XO + H2O → X(OH)2 (X means group 2A)

Examples include:

• Sodium oxide, which reacts with water to produce sodium hydroxide
• Magnesium oxide, which reacts with hydrochloric acid to form magnesium chloride
• Copper(II) oxide, which reacts with nitric acid to form copper nitrate

Properties of Oxide

The molecules that contain the group of H-O-X can behave normally as acids but when the hydroxide ion is produced they can behave as bases. The O-X bond will remain intact and become polar and the weak O-H bond will tend to break, releasing a proton when the H-O-X grouping is dissolved in water. The O-X bond will become ionic and breakdown in polar water if X has very low electronegativity. For example, when NaOH and KOH which are ionic substances dissolve in water they will produce basic solutions of the metal hydroxide. These principles can explain the base behavior when they are dissolved in water.