Short Answer TypeWrite three distinct features of chemisorptions which are not found in physisorptions.
(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?
Define the following terms:
i)Lyophilic colloid
ii) Zeta potential
iii) Associated colloids
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 :
Lyophobic sol and Lyophilic sol
Lyophilic sol: These are also called reversible sols. These are quite stable and cannot be easily coagulated. Example are Sols of organic substances like gelatin, gum, starch and proteins
Lyophobic sol: These are also called irreversible sols and these are unstable and can be easily coagulated due to lack of protecting layer around charged colloidal particles, they easily form a cluster. Hence, they got easily coagulated on the addition of small amount of electrolyte. Examples are Sols of inorganic substances like Arsenic (As2S3), Iron (Fe(OH)3 and platinum.
Write one difference in each of the following :
Homogeneous catalysis and Heterogeneous catalysis
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