Short Answer TypeWrite the dispersed phase and dispersion medium of the following colloidal systems:
(i) Smoke (ii) Milk
What are lyophilic and lyophobic colloids? Which of these sols can be easily coagulated on the addition of small amounts of electrolytes?
Write the differences between physisorption and chemisorption with respect to the following:
(i) Specificity
(ii) Temperature dependence
(iii) Reversibility and
(iv) Enthalpy change
What is meant by coagulation of a colloidal solution? Describe briefly any three methods by which coagulation of lyophobic sols can be carried out.
Define the following terms:
(i) Brownian movement
(ii) Peptization
(iii) Multimolecular colloids
(i) The continuous random zigzag motion of colloidal particles in the colloidal solution, when observed under an ultramicroscope, is called Brownian movement/motion.
(ii) Peptization is defined as the process of conversion of a precipitate into a colloidal solution by shaking it with the dispersion medium in presence of small amount of an electrolyte.
(iii) Multimolecular colloids are species having a size in the colloidal range (diameter < 1 nm) that are formed by the aggregation of a large number of atoms or small molecules of substances when dissolved in the dispersion medium.
Define the following terms giving an example of each:
(i) Associated colloids
(ii) Lyophilic sol
(iii) Adsorption
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