Page 1 :
3. Match List-I with List-II and select the correct, colloidal dimensions and carry electric charge, creating an electric field in the sewage tank,, answer using the codes given below the lists:, charged electrodes, get neutralized and settle, these particles migrate to the oppositely, down at the bottom. It will be seen that here,, 7., Formation of Deltas: The deltas at the, The, mouths of great rivers are formed by the, precipitation of the charged clay particles,, carried as suspension in the river water, by the, action of salts present in sea water., discharged and deposited as, are, The particles, 8., Cleansing of Water: Sometimes slight turbidity, is noticed in water. This is due to the presence of, negatively charged particles of very fine clay. The, addition of potash alum or aluminiumsulphate, furnishes the trivalent aluminium ions (Al3+), which cause the coagulation of the clay particles,, which, therefore, settle down leaving water in, mechanically., clear state., EXERCISE, MULTIPLE CHOICE QUESTIONS, - An albumin sol containing sodium chloride as, an impurity can best be get rid of this impurity, by:, List-I, List-II, A. Coagulation, 1. Scattering of light, (a) Dialysis, (c) Filtration, 2 A small quantity of ferric chloride solution is, added to freshly prepared ferric hydroxide, precipitate, when a reddish brown positively, charged sol is formed. This phenomenon is, called:, (b) Electrophoresis, B. Lyophilization, 2. Washing of precipitates, (d) Precipitation, C. Peptisation, 3. Purification of colloids, D. Tyndall effect, 4. Electrolyte, А ВС D, (a) 4, 3 2, la) Cataphoresis, (c) Emulsification, (b) Dialysis, (b) 2, 4, (d) Peptisation, (c) 3, 4, (d) 4, 3 1 2, 32, 1., 1.

Page 2 :
Only lighter gases show physical adsorp, Cloud bursts occur due to one of the following 10. Hardening of egg white (albumin) is process, emistry), P-66, (c), tion at low temperature, Which one is not a colloidal solution?, (b) Air, 4., (a) Smoke, (d), Activation energy of chemisorption, (d) Blood, activation energy of physical adsorption, (c) Ink, 5., of:, reasons:, Coagulation, (b) Sedimentation, (a) The clouds are attracted towards the, electrical charge on the earth, (a), (c), Peptisation, (b) Large amount of water is present in the, cloud, (d), Denaturation of protein, 11. Purple of Cassius is:, (a), (c) Dense clouds are present in the upper, atmosphere, A solution of AgNO3 in HNO3, (b), Colloidal solution of gold, (d) Mutual discharge of oppositely charged, clouds resulting in the coagulation of, water droplets, A colloidal solution of platinum, C colloidal solution of palladium, (c), (d), 12. Lyophilic sols are stable due to:, The migration of the dispersion medium of a, colloidal system under the influence of an, electric field when the dispersed particles are, prevented from moving is called:, (a) Cataphoresis, 6., Charge on the particles, Large size of the particles, Small size of the particles, (a), (b), (c), (d) Layer of dispersion medium on the, particles, (b) Electro-osmosis, (c) Electrophoresis, (d) Brownian movement, 13. At CMC, the surface molecules:, 7., The colloidal solutions of gold prepared by, (a), Decompose, different methods have different colours due to, (b) Become completely soluble, the:, (c), Associate, Presence of different types of foreign, (a), particles depending upon the method of, preparation of the colloid, (d) Dissociate, 14. Protective sols are:, (a), Lyophilic, (b) Lyophibic, (b) Different concentrations of gold, (c) Various forms of gold, (c), Both 1 and 2, (d) None of these, d) Presence of different size of the colloidal 15. Which property of the colloidal solution is, particles obtained in different methods., Coagulation of a colloidal sol depends upon:, (a) Valency and nature of the anion and, independent of the charge on the colloidal, particles?, 8., (b) Tyndall effect, (d) Electrophoresis, (a), Electro-osmosis, (c), Coagulation, cation, (b) pH of the solution, (c) Rate of addition of electrolyte, (d) All the above conditions, 16. Which of the following electrolytes is least, effective in causing flocculation of ferric, hydroxide sol ?, (a) K3[Fe(CN)6, (b) K2CrO4, (d) K2SO4, 9., Which of these is incorrect?, (c), KBr, (a) Some times physical adsorption pass over, to chemisorption on increasing the, temperature of the system., (b) Oxygen is adsorbed on charcoal but on, desorption it also releases CO and CO2, prefer to adsorb, (a) S2-,OH, (c) S Fe+, (b) As, Fe, (d) As, OH

Page 3 :
P-67, Colloidal States, 25. Which is the characteristic of a catalyst?, (a) It changes equilibrium point, (b) It initiates a reaction, colloid, The amount of gold required to protect, (c) It alters the rate of reaction, (c), the colloid, (d) It increases average KE of molecules, 26. Gold number is:, d None of the above, ld sol in the presence of 0.25 g of starch, the, congulation is just prevented. Starch has the, following gold number:, (a) The number of mg of lyophilic colloid, which should be added to 10 ml of ferric, hydroxide sol so as to prevent its, coagulation by the addition of 1 ml of, 10% sodium chloride solution, (b) 0.25, (a) 0.025, (c) 2.5, a Silver iodide is used for producing artificial, (d) 250, (b) The number of mg of lyophilic colloid, which should be added to 10 ml of, standard gold sol so as to prevent its, coagulation by the addition of 1 ml of, 10%, rains because silver iodide:, (a) Is easy to spray at high altitude, (b) Is easy to synthesize, I) Is insoluble in water, (c) The mg of gold salt to be added to a, lyophilic colloid to coagulate it, (d) The mg of an electrolyte required to, coagulate a colloid, id) Has crystal structure similar to ice, 21. Gelatin is often used as an ingredient in the, manufacture of ice-cream. The reason for this 27. Which of the following statement is wrong for, is:, lyophobic sol?, (a) Dispersed phase is generally in organic, material, (a) To improve the flavour, (b) To cause the mixture to solidify, (c) To stabilize the colloid and prevent crystal, growth, (b) Can be easily coagulated by small, addition of electrolyte, (c) Dispersed phase particles are poorly, hydrated and colloid is stabilised due to, charge on the colloidal particles, (d) Reversible in nature that is after coagulation, (d) To prevent the formation of a colloid, 22 Milk can be preserved by adding few drops of:, (a) Formic acid solution, (b) Formaldehyde solution, (c) Acetic acid solution, can be easily set into colloidal form, 28. Which of the following statements is not true, for a lyophobic sol?, d) Acetaldehyde solution, The pH range at which a hydrophilic sol has, no charge and is least stable is called:, (a) It can be easily solvated, (b) It carries charge, la The point of high electrical conductance, (c) The coagulation of this sol is irreversible, 10) The point of maximum electrical charge, gradient, (c) The flocculation point, (d) The isoelectric point, 44. Tyndall effect is observed in, in nature, (d) It is less stable in a solvent, 29. As2S3 sol has a negative charge. Capacity to, precipitate it is highest in:, (a) Solution, (a) AICI3, (b) NagPO4, (b) Precipitate, (c) Sol, (d) Vapours, (c) CaCl2, (d) K2SO4

Page 4 :
36. If the dispersed phase is a, dispersion medium is a solid, the colloid is, 30. Starch dispersed in hot water is an example of:, liquid and the, (a) Emulsion, known as:, (b) Hydrophobic sol, (a) A sol, (b) An emulsion, (c) Lyophilic sol, (d) Associated colloid, 31. Which of the following is most effective in, coagulating a femric hydroxide sol?, (c) A gel, 37. Zig-zag motion (erratic motion) of particles in, (d) A foam, colloid was observed by:, (a) Tyndall, (c) Robert Brown, (b) Zsigmondy, (a) KCI, (b) KNO3, (c), K2SO4, (d) K2SO4, (d) Thomas Graham, 38. On addition of one ml solution of 10% NaCl, to 10 ml gold sol in the presence of 0.25 gm of, starch, the coagulation is just prevented. Starch, has the following gold number:, 32. Sky looks blue due to:, Dispersion effect, (c), 33, Which one is an example of gel?, (a), (b) Reflection, Transmission, (d) Scattering, (a), Soap, (b) Cheese, (a) 0.025, (b) 0.25, (c) Milk, (d) Fog, (c) 0.5, (d) 250, 34. The random or zig-zag motior. of the colloidal 39. Tyndall effect would be observed in a:, particles in the dispersion medium is referred, (a) Solution, to as:, (b) Colloidal solution, (a) Electro-osmosis, (c) Precipitate, (b) Electrophoresis, (d) Solvent, 40. Ferric hydroxide sol is positively charged, colloid. The coagulating power of NO3, SO, (c) Brownian movement, (d) Tyndall effect, and PO ions would be in the order:, 35. Which of the following electrolytes is least, effective in causing flocculation of ferric, hydroxide sol?, (a) NO > SO > PO, (b) So > NO5 > PO, (c) PO > SO > NO3, (d) NO3 = SO = PO, (a) KalFe(CN)6], (b) K2CrO4, <., (c) KBr, (d) K2SO4, ANSWERS, MULTIPLE CHOICE QUESTIONS, 1., (a), 2., (d), 3., (a), 4., (b), 5., (d), 6. (b), 7., (d), 8., (a), 9., (e) 10. (d), 11. (b), 12., (a), 13., (c), 15. (b) 16. (c) 17. (c) 18. (d) 19. (c) 20., 14., (a), (d), 21. (c), 22., (b) 23. (d) 24., 25. (c) 26. (b) 27. (d) 28., (c), (a) 29., (a) 30. (c), 31. (d) 32., (d) 33. (b) 34., 35. (c) 36. (c) 37., (c), (c) 38., (d) 39. (b) 40., (c)