Define the following terms:
i)Lyophilic colloid
ii) Zeta potential
iii) Associated colloids
i) Lyophilic colloids are liquid loving colloids (Lyo means solvent and philic means loving). When these colloids are mixed with the suitable liquid, high force of attraction exists between colloidal particles and liquid. This result in the formation of very stable solution called lyophilic sol. These sols are formed by substances like gums, starch and proteins.
ii) Zeta Potential : zeta potential is the potential difference between the dispersion medium and the stationary layer of fluid attached to the dispersed particle.
iii) Association colloids are microheterogeneous systems in which the particles of the colloidal dispersed phase (micelles) are formed by the agglomeration of molecules or ions of the substance dissolved in the dispersion medium.
Classify colloids where the dispersion medium is water. State their characteristics and write an example of each of these classes.
OR
Explain what is observed when
(i) An electric current is passed through a sol
(ii) A beam of light is passed through a sol
(iii) An electrolyte (say NaCl) is added to ferric hydroxide solWrite one difference in each of the following :
Homogeneous catalysis and Heterogeneous catalysis
(i) Differentiate between adsorbtion and absorption.
(ii)Out of MgCl2 and AlCl3, which one is more effective in causing coagulation of negatively charged sol and why?
(iii)Out of sulphur sol and proteins, which one form multimolecular colloids?
