Long Answer Type(a) Which will absorb more gas, a lump of charcoal or its powder and why?
(b) Describe the preparation of the following colloidal solutions. Name the method used in each case (i) silver sol, (ii) sulphur sol.
Explain What is observed when:
(a) A beam of light is passed through a colloidal solution of As2S3
(b) An electrolyte (NaCl) is added to ferric hydroxide sol.
(c) An electric current is passed through a colloidal solution.
Short Answer TypeLong Answer TypeIllustrate with example:
(i) Lyophilic and Lyophobic sols.
(ii) Multimolecular and macromolecular colloids.
(iii) Homogeneous and Heterogeneous catalysis.
Short Answer TypeEnzymes are complex nitrogenous organic compounds which are produced by living plants and animals. They are actually protein molecules of high molecular mass and form colloidal solutions inwater.
There are a number of cavities present on the surface of colloidal particles of enzymes. These cavities are of characteristic shape and possess active groups such as -NH2 , -COOH, -SH, -OH, etc. These are actually the active centres on the surface of enzyme particles. The molecules of the reactant (substrate), which have complementary shape, fit into these cavities just like a key fits into a lock. On account of the presence of active groups, an activated complex is formed which then decomposes to yield the products.
Thus, the enzyme-catalysed reactions may be considered to proceed in two steps.
Step 1: Binding of enzyme to substrate to form an activated complex.
E + S → ES≠
Step 2: Decomposition of the activated complex to form product.
ES≠ → E + P
Long Answer Type
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