Study Material
SURFACE CHEMISTRY
Very Short Answer Questions
Q1. What is an interface? Give one example.
Q2. What is adsorption? Give one example.
Q3. What is absorption? Give one example.
Q4. Distinguish between adsorption and absorption. Give one example of each.
Q5. The moist air becomes dry in the presence of silica gel. Give reason for this.
Q6. Methylene blue solution when shaken with animal charcoal gives a colourless filtrate on filtration. Give the reason.
Q7. A small amount of silica gel and a small amount of anhydrous calcium chloride are placed separately in two corners of a vessel containing water vapour. What phenomena will occur?
Q10. Amongst adsorption, absorption which is a surface phenomena and why?
Q11. What is the name given to the phenamenon when both adsorption and absorption
Q12. Chalk stick dipped in an ink solution exhibits the following: a The surface of the stick retains the colour of the ink. b. Breaking the chalk stick, it is found still white from inside. Explain the above observations.
Q13. What are the factors which influence the adsorption of a gas on a solid?
Q14. Why is adsorption always exothermic ?
Q15. Give the signs of $ \delta H \,\, & \,\, \delta S$ when ammonia gas gets adsorbed on charcoal.
Q16. How many types of adsorption are known? What are they?
Q17. What types of forces are involved in physisorption of a gas on solid?
Q18. What type of Interaction occuring between gas molecules and a solid surface is responsible for chemisorption of the gas on solid.
Q19. Why chemisorption is called activated adsorption?
Q20. What is the difference between physisorption and chemisorption?
Q21. Out of physisorption and chemisorption, which can be reversed ?
Q22. How is adsorption of a gas related to its critical temperature ?
Q23. The critical temperature of $\ce{ SO2}$ is $\ce{630 K}$ and that of$\ce{ CH4}$ is $190K$. Which is adsorbed easily on activated charcoal ? Why?
Q24. Easily liquefiable gases are readily adsorbed on solids. Why?
Q25. Amongst $\ce{SO2, H2}$ which will be adsorbed more readily on the surface of charcoal and why?
Q26. Compare the enthalpy of adsorption for physisorption and chemisorption.
Q27. What is the magnitude of enthalpy of physical adsorption? Give reason for this magnitude.
Q28. What is the magnitude of enthalpy of chemisorption? Give reason for this magnitude.
Q29. Give any two applications of adsorption.
Q30. Why physisorption suffers from lack of specificity?
Q31. What is an adsorption isotherm? Write the equation of Freundlich adsorption isotherm.
Q32. In the Freundlich adsorption isotherm, mention the conditions under which, following graph will be true?
Q33. What role does adsorption play in hetergeneous catalysis?
Q34. What is the role of $\ce{ MnO2}$ in the preparation of $\ce{O2}$ from $\ce{KCIO3}$?
Q35. Define promoters and poisons in the phenomenon of catalysis.
Q36. What is homogeneous catalysis? How is it different from heterogeneous catalysis?
Q37. Give two examples for homogeneous catalytic reactions.
Q38. Give two examples for heterogeneous catalysis.
Q39. Give two examples which indicate the selectivity of heterogeneous catalysis.
Q40. Why zeolites are treated as shape selective catalysts ?
Q41. Which zeolite catalyst is used to convert alcohols directly into gasoline?
Q42. What are enzymes? What is their role in human body?
Q43. Name the enzymes obtained from soyabean source.
Q44. Can catalyst increase the yield of reaction?
Q45. Name any two enzyme catalyzed reactions. Give the reactions.
Q46. Name the enzymes used in - (a) Decomposition of urea into ammonia. (b) Conversion of proteins into peptides in stomach.
Q47. What enzymes are obtained from yeast?
Q48. At what ranges of temperature and pH. enzymes are active?
Q49. Represent diagramatically the mechanism of the enzyme catalysis.
Q50. Name any two industrially important heterogeneous catalytic reactions mentioning the catalysts used.
Q51. What is a colloidal solution? How is it different from a true solution with respect to dispersed particle size and homogeneity?
Q52. Name the dispersed phase and dispersion medium in the following colloidal systems (1) fog (ii) smoke (iii) milk.
Q53. What are lyophilic and lyophobic sols? Give one example for each type.
Q54. Explain the terms with suitable examples - (i) aerosol (ii) hydrosol
Q55. Explain why lyophilic colloids are relatively more stable than lyophobic colloids?
Q56. Give two examples of colloidal solutions of liquids dispersed in solid. What is the name given to the colloidal solution?
Q57. What is the difference between multimolecular and macromolecular colloids.? Give one example for each.
Q58. What are micelles ? Give one example.
Q59. How do micelles differ from a normal colloidal solutions?
Q60. Give two examples of associated colloids.
Q61. Can the same substance act both as colloid and crystalloid ?
Q62. Give two examples of lyophobic sols.
Q63. Give examples of colloidal system of (i) liquid in solid (ii) gas in solid
Q64. What type of substances form lyophobic sols ?
Q65. What is critical micelle concentration (CMC) and Kraft temperature$\ce{(T_k)}$?
Q66. Why lyophobic colloids are called irreversible colloids?
Q67. How a colloidal sol of arsenous sulphide is prepared?
Q68. What is peptization ?
Q69. What is dialysis? How is dialysis can be made fast?
Q70. What is collodion solution ?
Q71. How an ultrafilter paper is prepared from ordinary filter paper?
Q72. What is Tyndall effect ?
Q73. Under what conditions is Tyndall effect observed ?
Q74. Can Tyndall effect be used to distinguish between a colloidal solution and a true solution? Explain.
Q75. Sky appears blue in colour. Explain.
Q76. What is Brownian movement ?
Q77. What is the main cause for charge on a colloidal solution ?
Q78. What is electrokinetic potential or zeta potential?
Q79. Write the chemical formula of positively charged and negatively charged hydrated ferric oxide colloidal solutions.
Q80. Give the order of coagulating power of $\ce{CI^- , SO_4^{2-} , PO_4^{3-}}$ in the coagulation of positive sols.
Q81. Amongst $\ce{Na^+, Ba^{2+}, Al^{3+}}$ which coagulates negative sol readily and why?
Q82. A colloidal solution of Agl is positively charged when prepared from a solution containing excess of $\ce{Ag^+}$ ions and negatively charged when prepared from a solution containing excess of$\ce{ I^-}$ ions. Explain.
Q83. What is electrophoresis ?
Q84. What is electro osmosis ?
Q85. What is coagulation?
Q86. Define flocculation value.
Q87. State Hardy Schulze rule.
Q88. Coagulation takes place when sodium chloride solution is added to a colloidal solution of hydrated ferric oxide. Explain.
Q89. How are lyophobic solutions protected from phenomenon of coagulation.
Q90. What is protective colloid ?
Q91. What is an emulsion? Give two examples.
Q92. How emulsions are classified? Give one example for each type of emulsion.
Q93. What is an emulsifing agent?
Q94. What is demulsification? Name two demulsifiers.
Q95. How is artificial rain produced ?
Q96. Bleeding from fresh cut can be stopped by applying alum. Give reasons.
Q97. Deltas are formed at the points where river enters the sea. Why?
Q98. Name any two applications of colloidal solutions.
Q99. How can aerial pollution by colloidal particles of smoke be prevented? Explain.
Q100. Alum is used to purify water obtained from natural sources. Explain.
Q101. Why medicines are more effective in colloidal state?
Q102. How rubber is obtained from latex?
Q103. Name the type of emulsion to which milk belongs.
Q1. What is adsorption? Discuss the mechanism of adsorption of gases on solids.
Q2. What are different types of adsorption? Give any four differences between characteristics of these different types.
Q3. What do you understand by the terms given below (a) Absorption(b) Adsorption (c) Adsorbent and Adsorbate
Q4. Adsorption of a gas on the surface of solid is generally accompanied by decrease in entropy. Still it is a spontaneous process. Explain.
Q5. How can the constants k and n of the Freundlich adsorption equation be calculated?
Q6. How does the extent of adsorption depend upon (a) Increasing the surface area per unit mass of adsorbent (b) increasing temperature of the system (c) Increasing pressure of the gas
Q7. What is catalysis? How is catalysis classified? Give two examples for each type of catalysis.
Q8. Discuss the mechanism involved in adsorption theory of heterogeneous catalysis.
Q9. Discuss some features of catalysis by Zeolites.
Q10. Give brief account of mechanism of enzyme catalysis with suitable diagrams.
Q11. Discuss the factors that influence the catalytic activity of enzymes.
Q12. Name any six enzyme catalysed reactions.
Q13. What do you mean by activity and selectivity of catalysts?
Q14. How are colloids classified on the basis of physical states of components?
Q15. How are colloids classified on the basis of nature of the dispersion medium?
Q16. How are colloids classified on the basis of interaction between dispersed phase and dispersion medium ?
Q17. What is the difference between a colloidal sol, gel, emulsion and a foam?
Q18. What are lyophilic and lyophobic sols? Compare the two terms interms of stability and reversibility.
Q19. Name a substance whose molecules consist of lyophilic as well as lyophobic parts. Give its use in our daily life.
Q20. Describe Bredig's arc method of preparation of colloids with a neat diagram.
Q21. Name any four examples of preparation of colloids by chemical methods with necessary chemical equations.
Q22. Describe the purification of colloidal solutions by the phenomenon of dialysis with a neat diagram.
Q23. Explain the formation of micelles with a neat sketch.
Q24. Action of soap is due to emulsification and micelle formation. Comment.
Q25. Explain the phenomenon of Brownian movement giving reasons for the occurrence of this phenomena.
Q26. Name the four positively charged sols.
Q27. Name the four negatively charged sols.
Q28. Explain the terms Helmholtz electrical double layer and zeta potential. What are their significances in the colloidal solutions ?
Q29. Explain with a neat sketch the penomenon of electrophoresis.
Q30. Explain the following terms (1) electrophoresis (ii) coagulation (iii) Tyndall effect
Q31. Explain the phenomenon observed (i) When a beam of light is passed through a colloidal sol (ii) an electrolyte. NaCl is added to hydrated ferric oxide (iii) an electric current is passed through a colloidal solution
Q32. Describe cottrell smoke precipitator with a neat diagram.
Q33. 136. Among $\ce{NaCl, Na2SO4, Na3PO4}$ electrolytes, which is more effective for coagulation of hydrated ferric oxide sol and why?
Q34. Discuss how a lyophilic colloids protect a lyophobic colloids.
Q35. Discuss the use of colloids in (i) purification of drinking water (ii) Tanning (iii) Medicines
Q37. How do emulsifiers stabilize emulsion? Name two emulsifiers.
Q1. Explain the terms absorption, adsorption and sorption. Describe the different types of adsorption.
Q2. Discuss the characteristics of physical adsoprtion.
Q3. Discuss the characteristics of chemisorption.
Q4. Compare and contrast the phenomenon of physisorption and chemisorption.
Q5. What is an adsorption isotherm? Discuss the phenomenon of adsorption of gases on solids with the help of Freundlich adsorption isotherm.
Q6. Give a detailed account of applications of adsorption.
Q7. What is catalysis? How is catalysis classified? Give four examples for each type of catalysis.
Q8. Discuss the mechanism of heterogeneous catalysis.
Q9. What are enzymes? Explain in detail the enzyme catalysis, with necessary examples.
Q10. What are colloidal solutions? How are they classified? Give examples.
Q11. What are colloidal solutions? How are they classified? Give examples.
Q12. How are colloids classified on the basis of the nature of interaction between a dispersed phase and a dispersion medium? Describe an important characteristic of each class. Which of the sols need stabilising agents for preservation?
Q13. What are micelles? Discuss the mechanism of micelle formation and cleaning action of soap.
Q14. Describe the properties of colloids with necessary diagrams wherever necessary.
Q15. What are emulsions? How are they classified? Describe the applications of emulsions.