Short Answer TypeAnswer:
The process of Adsorption is an Exothermic Reaction. Thus according to Le-chatlier’s Principle, the magnitude of adsorption should increase with decrease in temperature. Infact it is found to be so in case of physical adsorption because vanderwaal’s forces are strong at low temperatures.
However, the chemisorption first increases with rise in temperature and then starts decreasing. The initial increase shows that like chemical reactions, chemisorption also needs activation energy.
If a plot is drawn between amount of gas adsorbed (x/m) and temperature at constant equilibrium pressure, then curve obtained for physical adsorption shows there is a regular decrease in adsorption with temperature rise. While for chemisorption it first increases and then shows regular decrease. Such curves are known as Adsorption Isobars.
(a) How can a colloidal solution and true solution of the same colour be distinguished from each other ?
(b) List four applications of adsorption.
Explain the following observations:
(a) Lyophilic colloids are more stable than lyophobic colloid.
(b) Coagulation takes place when sodium chloride solution is added to a colloidal solution of ferric hydroxide.
(c) Sky appears blue in colour.
(a) In which of the following does adsorption take place and why?
(i) Silica gel placed in the atmosphere saturated with water.
(ii) Anhydrous CaCl2 placed in the atmosphere saturated with water.
(b) How does BF3 act as a catalyst in industrial process?
(c) Give an example of shape selective catalysis.
Long Answer Type(a) Of NH3 and CO2 which will be adsorbed more readily on the surface of charcoal and why?
(b) How are multimolecular colloids different from macro-molecular colloids?
(c) State the principle of electro-dialysis.
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