Question

Write the properties of the following:

Basic oxides

Answer 1

1. Basic oxides: A basic oxide is an oxide that exhibits the property of a base.
2. Examples of basic oxides: Magnesium oxide (MgO), Sodium oxide $\left({\mathrm{Na}}_2\mathrm{O}\right)$.
3. Characteristics of basic oxides:

• Basic oxides are formed when Oxygen reacts with metals like Magnesium (Mg), Sodium (Na) etc.
• Basic oxide reacts with water to form a base. For example; the reaction of Magnesium oxide with water gives Magnesium hydroxide which is shown as:

$$\begin{gathered} \mathrm{MgO}\left(\mathrm{s}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\to \mathrm{Mg}{\left(\mathrm{OH}\right)}_2\left(\mathrm{aq}\right) \\ (\mathrm{Magnesium}\mathrm{oxide})\left(\mathrm{Water}\right)(\mathrm{Magnesium}\mathrm{hydroxide}) \end{gathered}$$

• As a base is formed on addition of water to them, they are also called as the anhydrides of bases. Example: Sodium oxide is the anhydride of base Sodium hydroxide (NaOH).
• Since they are basic, they react with an acid to form a salt. For example, the reaction of Magnesium oxide with Sulphuric acid gives Magnesium sulphate and water which is shown below.

$$\begin{gathered} \mathrm{MgO}\left(\mathrm{s}\right)+{\mathrm{H}}_2{\mathrm{SO}}_4\left(\mathrm{l}\right)\to {\mathrm{MgSO}}_4\left(\mathrm{aq}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right) \\ (\mathrm{Magnesium}\mathrm{oxide})(\mathrm{Sulphuric}\mathrm{acid})(\mathrm{Magnesium}\mathrm{hydroxide})\left(\mathrm{Water}\right) \end{gathered}$$

• The aqueous solution of basic oxides turns red litmus blue because of their basic nature.
• Acidic oxides are ionic compounds formed by the exchange of electrons.
• They possess high melting and boiling points.
• They conduct electricity in the molten state.