Question

How is an acid prepared from a non-metal and a base from a metal? Give equation.

Answer 1

Preparation of acids from non-metals: Acids can be prepared from non-metals by direct combination of non-metals with hydrogen and also by oxidation of non-metals with nitric acid.

1. Oxidation of non-metals: Non-metals, such sulphur and phosphorous, undergo oxidation by nitric acid, producing corresponding acids along with water and respective oxides.

$$\begin{gathered} \mathrm{S}+6{\mathrm{HNO}}_3\stackrel{}{\to }{\mathrm{H}}_2{\mathrm{SO}}_4+2{\mathrm{H}}_2\mathrm{O}+6{\mathrm{NO}}_2 \\ \mathrm{Sulphur}\mathrm{Nitric}\mathrm{acid}\mathrm{Sulphuric}\mathrm{acid}\mathrm{Water}\mathrm{Nitrogen}\mathrm{dioxide} \end{gathered}$$

2. By direct combination of non-metals with hydrogen: Non-metals react directly with hydrogen, forming acidic gases whose solutions are known as acids.

$$\begin{gathered} {\mathrm{H}}_2+{\mathrm{Cl}}_2\stackrel{}{\to }2\mathrm{HCl} \\ \mathrm{Hydrogen}\mathrm{Chlorine}\mathrm{Hydrochloric}\mathrm{acid} \end{gathered}$$

Preparation of bases from metals: Bases can be prepared from metals by heating metals directly in the presence of air and by reacting metals with water.

1. Direct heating of metals: By heating metals directly in the presence of air, metal oxides are formed; these metal oxides are bases.

$$\begin{gathered} 2\mathrm{Mg}+{\mathrm{O}}_2\stackrel{}{\to }2\mathrm{MgO} \\ \mathrm{Magnesium}\mathrm{Oxygen}\mathrm{Magnesium}\mathrm{oxide} \end{gathered}$$

2. By reacting with water: Highly reactive metals when reacted with water form soluble bases (called alkalis) and liberate hydrogen gas.

$$\begin{gathered} 2\mathrm{Na}+{\mathrm{H}}_2\mathrm{O}\stackrel{}{\to }2\mathrm{NaOH}+{\mathrm{H}}_2 \\ \mathrm{Sodium}\mathrm{Water}\mathrm{Sodium}\mathrm{hydroxide}\mathrm{Hydrogen} \end{gathered}$$