(N/A) The phenomenon of adsorption has numerous applications. Important ones are listed here:
$(i)$ Production of high vacuum: Remaining traces of air can be adsorbed by charcoal from a vessel evacuated by a vacuum pump to create a very high vacuum.
$(ii)$ Gas masks: Gas masks,which consist of activated charcoal or a mixture of adsorbents,are used in coal mines to adsorb poisonous gases.
$(iii)$ Control of humidity: Silica and aluminium gels are used as adsorbents to remove moisture and control humidity.
$(iv)$ Removal of colouring matter from solutions: Animal charcoal removes colours from solutions by adsorbing coloured impurities.
$(v)$ Heterogeneous catalysis: Adsorption of reactants on the solid surface of catalysts increases the reaction rate. Examples include the manufacture of ammonia using iron,the manufacture of $H_{2}SO_{4}$ by the contact process,and the use of nickel in the hydrogenation of oils.
$(vi)$ Separation of inert gases: Due to differences in the degree of adsorption,a mixture of noble gases can be separated by adsorption on coconut charcoal at different temperatures.
$(vii)$ Curing diseases: Many drugs are used to kill germs by getting adsorbed on them.
$(viii)$ Froth floatation process: Low-grade sulphide ores are concentrated by separating them from silica and other earthy matter using pine oil and a frothing agent.
$(ix)$ Adsorption indicators: Surfaces of precipitates like silver halides adsorb dyes such as eosin or fluorescein,producing a characteristic colour at the end point.
$(x)$ Chromatographic analysis: Based on the phenomenon of adsorption,this technique finds numerous applications in analytical and industrial fields.