Tiêu đề DPP-1 SOLUTION.pdf ✅

CLASS : XIth SUBJECT : CHEMISTRY DATE : DPP No. : 1 1 (d) Electrophoresis is movement of colloidal particles under the influence of electric field. 2 (d) Lyophilic sols are self stabilizing because these sols are reversible and are highly hydrated in the solution. 3 (c) All these are liquid aerosol systems, i.e., liquid dispersed in gas. 4 (b) Hydrolysis of ester catalysed by a proton is acid-base catalysis. 5 (c) An example of autocatalysis. 6 (c) Freundlisch adsorption isotherm is : X m = KP 1/n If P⟶0; n = 1 X m = KP If P is high; n = 0 X m = KP 0 7 (a) Colloidal solution of gold is called purple of cassius 8 (b) According to Freundlich equation, X m ∝ p 1/nor X m = kp 1/n or log X m = log kp 1/n or log X m = log k + 1 n log p 9 (c) CO gets adsorbed on active centres of Fe. 10 (a) The conversion of freshly prepared suspension into colloid is known as peptisation and those substances which help for such a conversion are known as peptising agent. Topic :- SURFACE CHEMISTRY Solutions
11 (b) The graph plotted between amount of substance adsorbed and on the given pressure at constant temperature is known as adsorption isotherm 12 (a) Tyndall effect is shown by colloidal solution due to scattering of light by their particles. 13 (a) The definition of negative catalyst. 14 (a) Chlorophyll is a compound. 15 (b) Dodecyl trimethyl ammonium chloride C12H25(CH3 )3NCl on dissolution forms C12H25 (CH3 )3N + and Cl ― ions. The former possesses hydrophilic ( ― N +) and hydrophobic [C12 H25(CH3 )― 3 ] parts. 16 (c) It is w/o type emulsion. 17 (a) Colour of colloidal solution depends upon particle size. As the particles size increases, the colour of gold sol changes from red to blue and finally to golden. 18 (d) In medical field, colloidal gold is used as tonic to raise vitality of human systems 19 (b) It is the definition of thixotropy, a property of gel. 20 (b) Catalyst in finely powdered state possesses larger surface area and more active centres and thus, becomes more effective.
ANSWER-KEY Q. 1 2 3 4 5 6 7 8 9 10 A. D D C B C C A B C A Q. 11 12 13 14 15 16 17 18 19 20 A. B A A A B C A D B B