Question

You are provided with magnesium ribbon and sulphur powder. Explain with the help of activity that metal oxides are basic and oxides of non-metals are acidic.

Answer 1

To check the activity of metal oxides and non-metal oxides:

1. When magnesium is exposed to the air and heated, there is the formation of oxide of magnesium. When this compound is dissolved in the water, the formation of magnesium hydroxide takes place. After that dip, the red litmus paper into it turns blue. Hence, it is basic in nature.
   $$\begin{gathered} 2\mathrm{Mg}\left(\mathrm{s}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)\to 2\mathrm{MgO}\left(\mathrm{s}\right) \\ \mathrm{MgO}\left(\mathrm{s}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\to \mathrm{Mg}{\left(\mathrm{OH}\right)}_2\left(\mathrm{aq}\right) \end{gathered}$$
2. When sulphur is exposed to the air and heated, there is the formation of sulphur dioxide. When this compound is dissolved in the water, there is the formation of acid sulfurous acid takes place. after that dip, the blue litmus paper into it turns red. Hence, it is acidic in nature.

$$\begin{gathered} \mathrm{S}\left(\mathrm{s}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)\to {\mathrm{SO}}_2\left(\mathrm{g}\right) \\ {\mathrm{SO}}_2\left(\mathrm{g}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\to {\mathrm{H}}_2{\mathrm{SO}}_3\left(\mathrm{aq}\right) \end{gathered}$$

Therefore, it is proved that metal oxides are basic and oxides of non-metals are acidic.