Question

Differentiate between acidic and basic oxides.

Answer 1

Acidic oxide

Basic oxide

Acidic oxides (also known as acid anhydrides) are formed when non-metal reacts with oxygen. Examples of acidic oxides are carbon dioxide $\left({\mathrm{CO}}_2\right)$, nitrogen dioxide $\left({\mathrm{NO}}_2\right)$, sulfur dioxide $\left({\mathrm{SO}}_2\right)$, etc. They have covalent bonds. Acidic oxides usually have low melting and boiling points except for compounds like boric oxide $\left({\mathrm{B}}_2{\mathrm{O}}_3\right)$ and silicon dioxide$\left({\mathrm{SiO}}_2\right)$ They do not react with acid. They react with a base from salt and water. $\underset{\mathrm{Carbon}\mathrm{dioxide}}{{\mathrm{CO}}_2\left(\mathrm{g}\right)}+\underset{\mathrm{Sodium}\mathrm{hydroxide}}{2\mathrm{NaOH}\left(\mathrm{s}\right)}\to \underset{\mathrm{Sodium}\mathrm{sulfite}}{{\mathrm{Na}}_2{\mathrm{SO}}_3\left(\mathrm{s}\right)}+\underset{\mathrm{Water}}{{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}$ Acidic oxides react with water and form acid. $\underset{\mathrm{Sulfur}\mathrm{trioxide}}{{\mathrm{SO}}_3\left(\mathrm{g}\right)}+\underset{\mathrm{water}}{{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}\to \underset{\mathrm{Sulfuric}\mathrm{acid}}{{\mathrm{H}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)}$ In this reaction, sulfur trioxide (an acidic oxide) reacts with water to form sulfuric acid.

Basic oxides (also known as basic anhydrides) are formed when a metal reacts with oxygen. Examples of basic oxides are calcium oxide $\left(\mathrm{CaO}\right)$, magnesium oxide $\left(\mathrm{MgO}\right)$, zinc oxide $\left(\mathrm{ZnO}\right)$, etc. They have ionic bonds. Basic oxides usually have high melting and boiling points. They react with acid to form salt and water. $\underset{\mathrm{Magnesium}\mathrm{oxide}}{\mathrm{MgO}\left(\mathrm{s}\right)}+\underset{\mathrm{Hydrochloric}\mathrm{acid}}{\mathrm{HCl}\left(\mathrm{aq}\right)}\to \underset{\mathrm{Magnesium}\mathrm{chloride}}{{\mathrm{MgCl}}_2\left(\mathrm{aq}\right)}+\underset{\mathrm{Water}}{{\mathrm{H}}_2\mathrm{O}}\left(\mathrm{l}\right)$ They do not react with base. Basic oxides react with water (except copper(II) oxide $\left({\mathrm{Cu}}_2\mathrm{O}\right)$, beryllium oxide$\left(\mathrm{BeO}\right)$, etc) and form a base. $\underset{\mathrm{Lithium}\mathrm{oxide}}{{\mathrm{Li}}_2\mathrm{O}\left(\mathrm{s}\right)}+\underset{\mathrm{water}}{{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}\to \underset{\mathrm{Lithium}\mathrm{hydroxide}}{2\mathrm{LiOH}\left(\mathrm{aq}\right)}$ In this reaction, lithium oxide (a basic oxide) reacts with water to form lithium hydroxide (a base).