Tiêu đề 5.SURFACE CHEMISTRY.pdf ✅

P a g e | 1 5.SURFACE CHEMISTRY Single Correct Answer Type 1. For adsorption of gas on solid surface, the plots of log x/m vs. log P is linear with a slope equal to : a) K b) log K c) l/nK d) l/n (n being integer) 2. Which is not correct for catalyst? It : a) Enhances the rate of reaction in both directions b) Changes enthalpy of reaction c) Reduces activation energy of reaction d) Specific in nature 3. The magnitude of colligative properties in all colloidal dispersions is .....than solution : a) Higher b) Lower c) Both (a) and (b) d) None of these 4. Which one is hydrophobic in nature? a) Gelatin b) Sulphur c) Starch d) Protein 5. a) Neutralization reaction b) Homogeneous catalysis c) Heterogeneous catalysis d) Irreversible reaction 6. Decomposition of urea into NH3 and CO2 is followed by the action of enzyme : a) Urease b) Pepsin c) Trypsin d) None of these 7. Adsorption is accompanied by the evolution of heat. So, according to Le-Chatelier principle the amount of substance adsorbed should a) Increase with decrease in temperature b) Increase with increase in temperature c) Decrease with decrease in temperature d) Decrease with increase in temperature 8. Which one of the following equation represents Freundlich adsorption isotherm? a) x m = kp b) x m = kp n c) log x m = kp n d) log x m = kn log p 9. The number of moles of lead nitrate needed to coagulate 2 moles of colloidal [AgI]I − is a) 2 b) 1 c) 1/2 d) 2/3 10. Surfactant molecules or ions cluster together as micelles which a) Due to their hydrophilic tails tend to congregate b) Due to their hydrophobic heads provide protection c) Are colloid sized clusters of molecules d) None of the above 11. The temperature above which micelle formation occurs is : a) Critical temperature b) Charles’ temperature c) Inversion temperature d) Kraft’s temperature 12. By dividing the catalyst into fine powder there will be increase in a) Surface area b) Free valancies c) Active centres d) All of these 13. Washing soap can be prepared by saponifying alkali with oil of : a) Rose oil b) Paraffin oil c) Ground nut oil d) kerosene 14. Platinum is used as a catalyst in : a) Oxidation of ammonia to form nitric acid b) Hardening of oils c) Production of synthetic rubber d) Synthesis of methanol
P a g e | 2 15. A colloidal solution always has at least : a) One phase b) More than two phases c) A true solution d) Two phases 16. Milk can be preserved by adding a few drops of : a) Formic acid solution b) Formaldehyde solution c) Acetic acid solution d) Acetaldehyde solution 17. Addition of FeCl3 to K4[Fe(CN)6] in dilute and cold solution gives : a) Prussian blue sol b) Fe4 [Fe(CN)6 ]3 sol c) Positive sol d) All of these 18. Colloidal solution commonly used in treatment of skin diseases is : a) Colloidal sulphur b) Colloidal silver c) Colloidal gold d) Colloidal antimony 19. The substance that gets adsorbed on the surface of solid is called a) Adsorbate b) Adsorbent c) Micelle d) Absorbent 20. Which of the following is not correct? a) Enthalpy of physical adsorption is less compared to enthalpy of chemical adsorption b) Milk is an example of emulsion c) Physical adsorption increases with the increase in temperature d) Smoke is an aerosol 21. Which of the following characteristics is not correct for physical adsorption? a) Adsorption on solids is reversible b) Adsorption increases with increase in temperature c) Adsorption is spontaneous d) Both enthalpy and entropy of adsorption are negative 22. Which of the following statements is incorrect? a) Physical adsorption occurs at very low temperature and chemisorptions occur at all temperature b) The magnitude of chemisorption decreases with rise in temperature and physisorption increases with rise in temperature c) Chemisorption is irreversible and physisorption is reversible d) In physisorption, the activation energy of desorption is very low and in chemisorption, the activation energy of desorption is very high 23. Which of the following has maximum coagulation power with ferric hydroxide sol? a) Cryolite b) K2C2O4 c) K3 [Fe(CN)]6 d) K4[Fe(CN)6] 24. The critical micelle concentration (CMC) is a) The concentration at which micellisation starts b) The concentration at which the true solution is formed c) The concentration at which one molar electrolyte is present per 1000 g of the solution d) The concentration at which ∆H = 0 25. A dilute solution of litmus becomes colourless on shaking with charcoal. This is due to : a) Absorption b) Adsorption c) Chemical reaction d) Both (a) and (b) 26. Which of the following is an example for heterogeneous catalysis reaction? a) 2SO2 (g) + O2 (g) NO (g) → 2SO3(g) b) Hydrolysis of aqueous sucrose solution in the presence of aqueous mineral acid c) 2H2O2 (l) pt(s) → 2H2O(l) + O2(g) d) Hydrolysis of liquid in the presence of aqueous mineral acid 27. Which of the following is true in respect of adsorption? a) ∆G < 0; ∆S > 0; ∆H < 0 b) ∆G < 0; ∆S < 0; ∆H < 0 c) ∆G > 0; ∆S > 0; ∆H < 0 d) ∆G < 0; ∆S < 0; ∆H > 0
P a g e | 3 28. Which is a homogeneous system? a) A solution of sugar in water b) Concrete c) Muddy water d) Bread 29. Which of the following is the most effective in the coagulation of gold sol? a) NaNO3 b) MgCl2 c) Na3PO4 d) K4 [Fe(CN)6 ] 30. Which of the following is not a characteristic of chemisorption? a) ∆H is the order of 400 kJ b) Adsorption is irreversible c) Adsorption may be multimolecular layer d) Adsorption is specific 31. Select wrong statement. a) If a very small amount of AlCl3is added to gold sol, coagulation occurs, but if a large quantity of AlCl3is added, there is no coagulation. b) Organic ions are more strongly adsorbed on charged surfaces in comparison to inorganic ions. c) Both emulsifier and peptising agents stabilise colloids but their actions are different. d) Colloidal solutions are thermodynamically stable. 32. The size of colloidal particles is in between a) 10−7 − 10−9 cm b) 10−9 − 10−11cm c) 10−5 − 10−7 cm d) 10−2 − 10−3 cm 33. The Brownian movement occurs in : a) Colloidal solution b) True solution c) Suspension having size < 500 mμ d) All of the above 34. Dyeing of fibre involves the process of : a) Adsorption b) Absorption c) Sorption d) All of these 35. Which adsorption takes place at low temperature? a) Physical b) Chemical c) Both (a) and (b) d) None of these 36. Term catalyst was given by a) Rutherford b) Berzilius c) Wohler d) Kolbe 37. The cotterells precipitator is used to : a) Neutralize charge on carbon particles in air in smoke b) Coagulate carbon atoms of smoke c) Bring in cataphoresis in carbon particles d) All of the above 38. A catalyst is a substance which a) Is always in the same phase as in the reactions b) Alters the equilibrium in a reaction c) Does not participate in the reaction but alters the rate of reaction d) Participates in the reaction and provide an easier pathway for the same 39. Multimolecular colloids are present in a) Soap solution b) Sol of proteins c) Sol of gold d) All of these 40. The rate of a certain biochemical reaction catalysed by an enzyme in human body is 104 times faster than when it carried out in the laboratory. The activation energy of this reaction : a) Is zero b) Is different in two cases c) Is the same in both the cases d) None of the above 41. At CMC (critical micelle concentration), the surfactant molecules undergo a) Dissociation b) Micelle formation c) Both (a) and (b) d) None of these 42. Activated charcoal is used to remove colouring matter from pure substances. It works by
P a g e | 4 a) Oxidation b) Reduction c) Bleaching d) Adsorption 43. Lyophobic colloids are : a) Reversible colloids b) Irreversible colloids c) Protective colloids d) Gum, proteins 44. The size of the colloid particles is : a) > suspension particles b) < suspension particles c) < true solution particles d) None of these 45. Emulsions can be destroyed by a) The addition of an emulsifier which tend to form an emulsion of the same type b) Freezing c) Both (a) and (b) d) None of the above 46. Which characteristic of adsorption is wrong? a) Physical adsorption in general decreases with temperature b) Physical adsorption in general increases with temperature c) Physical adsorption is a reversible process d) Adsorption is limited to the surface only 47. Gelatin is often used as an ingredient in the manufacture of ice-cream. The reason for this is : a) To prevent the formation of a colloid b) To stabilize the colloid and prevent crystal growth c) To cause the mixture to solidify d) To improve the flavour 48. Blood contains : a) Positively charged particles b) Negatively charged particles c) Neutral particles d) Negatively as well as positively charged particles 49. The curve showing the variation of pressure with temperature for a given amount of adsorption is called a) Adsorption isobar b) Adsorption isotherm c) Adsorption isostere d) Adsorption isochore 50. When white light is passed through a colloidal solution containing fine suspended particles of gold, then the scattered light seen in a direction different from that of the incident light is : a) Yellow coloured b) Blue coloured c) Green coloured d) Red coloured 51. Emulsions of polyvinylacetate are used in : a) Polishes b) Latex paints c) Fire works d) Rayons 52. Peptization denotes a) Digestion of food b) Hydrolysis of proteins c) Breaking and dispersion into colloidal state d) Precipitation of solid from colloidal dispersion 53. Which characteristic is the most important factor in giving rise to peculiar properties of colloids? a) Large size b) Small size c) High charge density d) High ratio of surface are to the volume 54. Alum helps in purifying water by : a) Forming Si complex with clay particles b) Sulphate part which combines with the dirt and removes it