Tiêu đề DPP-10 SOLUTION.pdf ✅

CLASS : XIth SUBJECT : CHEMISTRY DATE : DPP No. : 10 1 (d) Sols having water as dispersion medium (D.M.) are called aquasol. If benzene is D.M., it is benzosol. If alcohol is D.M., it is alcosol. 2 (b) Both process of adsorption and absorption taking place simultaneously are referred as Sorption. 3 (d) In adsorption, due to forces of attraction, ∆H is negative and as the particles came closer entropy of the system decrease, ie, ∆S is negative, hence T∆S is also negative 4 (c) Viscosity of hydrophilic is much higher than dispersion medium. Surface tension being much lesser than dispersion medium (water). This is due to higher concentration of dispersed phase in water due to water loving nature. 5 (b) Coagulation is the phenomenon of conversion of colloidal sol into precipitate while in peptization, a fresh precipitate is converted into sol by adding electrolyte. Hence, it is clear that peptization does not involve coagulation. 6 (c) BaSO4is insoluble in water and thus, it does not from true solution with water. 7 (b) On passing H2S through a cold solution of an oxidant, colloidal sulphur is formed. 8 (a) The physical state changes but chemically it remains same. 9 (b) A catalyst lowers the activation energy and increases the rate of reaction. It is not consumed during reaction. 10 (a) C12H22O11 Maltase Maltase 2C6H12O6 Glucose Topic :- SURFACE CHEMISTRY Solutions
11 (a) SO2(g) + (1/2) O2(g) Pt(s) SO3 (g) 12 (b) The optimum temperature for production of ammonia by Haber’s process is 500°C. If the temperature is lowered down then production of ammonia becomes slow down 13 (a) Solvent hating sols are lyophobic or in other words dispersed phase has less affinity for solvent. 14 (b) Smaller the value of gold number, greater will be the protecting power of the protective colloid. Hence, protective nature of A, B and C is as Colloidal solution : A > B > C Gold number : 0.01 2.5 20 15 (b) Catalyst lowers the activation energy or brings down the threshold energy barrier. 16 (d) Oil and grease are adsorbed into the hydrophobic centre of detergent micelle and washed away. 17 (a) Catalyst decreases the activation energy and thus, chemical process undergoes through a new path of lower energy 18 (c) (i)Dialysis is the method of separating particles of colloids from those of crystalloids by diffusion of mixture through perchament membrane. (ii)Ultrafiltration is the method of separating particles of electrolyte from colloidal particle by filtering through ultrafilter paper. (iii)Electrophoresis is the movement of colloidal particles under influence of electric field. (iv) Peptization is a process of passing of precipitate into colloidal particle on addition of suitable electrolyte. ∴ Peptization is correct answer. 19 (c) The continuous rapid zig-zag motion by a colloidal particle in the dispersion medium is called Brownian movement 20 (b) In Haber’s process, a mixture of iron powder and molybdenum powder is used as catalyst Fe Mo N2 + 3H2 2NH3
ANSWER-KEY Q. 1 2 3 4 5 6 7 8 9 10 A. D B D C B C B A B A Q. 11 12 13 14 15 16 17 18 19 20 A. A B A B B D A C C B