Tiêu đề DPP-6 SOLUTION.pdf ✅

CLASS : XIth SUBJECT : CHEMISTRY DATE : DPP No. : 6 1 (d) These are different forms of Freundlich equation. 2 (c) Initially Pt asbestos was used. Now-a-days a relatively cheaper catalyst V2O5 is used. Also it is not poisoned by CO and As2O3. 3 (b) Adsorbent is the surface on which adsorption occurs 4 (c) In Cottrell’s precipitator, the charged particles are attracted towards the walls of precipitator, here they lose their charge and coagulate. Hence, the basic principle of Cottrell’s precipitator is the neutralisation of charge on colloidal particles. 5 (d) Freundlich adsorption isotherm gives relationship between pressure and amount of substrate adsorbed. x/m = kp 1 n (where, x/m = amount adsorbed ,p = pressure) or x = m.kp 1 n or x/m = kp ―n ∴ All equations represent Freundlich adsorption isotherm. 6 (c) Butter is an w/o emulsion having fat dispersed in water. 7 (b) Peptisation is a process in which freshly prepared precipitate disintegrates into colloidal solution 8 (a) A negative catalyst is one which lowers the rate of chemical reaction. eg, Addition of chloroform to H2O2 prevents the decomposition of CHCl3 to a great extent 9 (a) Gold no.is the amount of lyophilic in mg which just protect 10 mL gold sol against coagulation by 1 mL of 10% NaCl solution. It is a measure of protective power of lyophilic colloids. Topic :- SURFACE CHEMISTRY Solutions
10 (b) Suspension Colloidal solution True solution Particle size >100 nm 1nm-100nm < 1 nm Colloidal solution is a heterogeneous solution which contains particles of intermediate size. The particles of a colloidal solution have diameters between 1 to 100 nm. Colloidal solution shows the optical property (i.e.,Tyndall effect and Brownian movement). 11 (c) Lyophilic possesses solvent loving nature and thus, a thin layer of dispersed phase is formed around sol particles. 12 (d) Gold number is the number of milligrams of a hydrophilic colloid that will just prevent the coagulation of 10 mL of a gold sol on addition of 1 mL of 10% NaCl solution. ∴ Gold number =0.25 × 1000=250 13 (d) Sodium stearate is an example of associated colloids. Colloidal solution of enzymes, proteins, cellulose and starch are the examples of macromolecular colloids. 14 (d) MnO2speeds up the reaction. 16 (b) Blue colour of the sky and red colour of the red sun sets are due to scattering of light from particles of dust in the atmosphere 17 (c) AlCl3 in Friedel-Crafts reaction acts as Lewis acid to produce electrophile. 18 (d) Potassium stearate is an example of associated colloid or micelle. 19 (d) Coagulating power of an electrolyte for arsenioussulphide decreases as Al3+ > Ba2+ > Na+. 20 (d) A biological catalyst is an enzyme.
ANSWER-KEY Q. 1 2 3 4 5 6 7 8 9 10 A. D C B C D C B A A B Q. 11 12 13 14 15 16 17 18 19 20 A. C D D D D B C D D D