Q9/15D/04-15 Reg. No

St. Joseph’s College of Arts & Science (Autonomous)

St. Joseph’s College Road, Cuddalore – 607001 PCH1015S – REACTION KINETICS, ELECTRODE KINETICS AND PHOTO CHEMISTRY Time : 3 hrs Max Marks :75 SECTION – A (20X1=20) Answer ALL Questions I. Choose the correct answer

Reaction kinetics, Electrode kinetics and Photo chemistry PCH1015S Semester-IV – (set-2) Time : 3 hrs Max Marks :75 SECTION A (20x1=20) Answer ALL questions: I Choose the Correct Answer (10x1=10 marks) 1. Which is Brønsted catalysis equation for acid catalysis? a) log k =  logKa + C b) log 1/k =  logKa + C c) log k =  2 log1/Ka + C d) log k =  logKa - C 2. Which equation is used to relate rate and free energy of activation? a) Einstein b) Henderson c) Gibb’s d) Eyring 3. Using Langmuir isotherm, under high pressure, the extent of adsorption is a)  1/P b)  P c)  2 P d) independent of pressure

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Q9/15D/04-15 4. Dehydration of 2-methyl-2-butanol is an example for a) higher order reaction b) complex reaction c) simple reaction d) elementary reaction 5. Which of the following 0.01M solution will have greater ionic strength a) Al2(SO4) b) NaCl c) K2SO4 d) CaCl2 6. In Debye–Hückel limiting law, the activity coefficient is inversely proportional to a) charge number of ion species b) elementary charge c) Avogadro's number d) temperature of the solution 7. Which transition is spin-forbidden? a) vibrational relaxation b) inter system crossing c) fluorescence d) all the above 8. Relaxation of the excited state to its lowest vibrational level is called a) inter system crossing b) vibrational relaxation c) fluorescence excitation d) electron excitation 9. The electromagnetic radiation used in radiation chemistry is a) x-rays only b) UV-rays only c) visible rays only d) X- or -rays 10. The quantum yield for H2-CI2 photochemical reaction varies between a) 104-106 b) 10-4-10-6 c) 101-102 6 9 d) 10 -10

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Q9/15D/04-15 II Fill in the blanks (5X1=5 marks) 11. Enthalpy, Entropy and free energy of activation are related as _________ 12. Effect of temperature on reaction rate is given by ___________theory 13. Hydrolysis of diester is an example for ______________ reaction. 14. An example for photo-physical phenomenon is _______. 15. ______ junction is used in photovoltaic cell. III. Match the following = 5 marks) 16. Guoy-Chapman adsorption 17. BET adsorption 18. Fast reaction 19. Light intensity 20. Fluorescence

(5x1 Multi-molecular Actinometry Light emission electrical double layer Stopped flow method

Section-B (10 X 2 = 20 marks) Answer any TEN questions 21. Write eyring equation relating enthalpy and entropy of activation. 22. What is kinetic isotopic effect? 23. What is flammability limits? 24. Write about flash photolysis. 25. Calculate the ionic strength of 0.15molal NaCl solution. 26. Define activity and activity co-efficient. 27. Write quantum yield and any two examples for phosphorescence. 28. What are excimers and exciplexes 29. Write any two characteristics of hydrated electron. 30. Give an example for photo-isomerization reaction. 31. Draw BET plot for adsorption. 32. Show schematic graphical representation for stern model.

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Q9/15D/04-15 Section –C (5 X 7 = 35 marks) Answer any FIVE questions 33. a) Write the rate constant, as per collision theory of reaction rate. (2) b) For a reaction, if the Ea is 205.8 kJ/mol and rate constant is 1.33 X 10-4 s-1 at 127C. Calculate the standard entropy of activation. (3) c) Write is Brønsted catalysis law for acid and base catalysis. (2) 34. a) Derive Langmuir adsorption isotherm. (3) b) Draw Langmuir’s plot for the kinetics of gaseous reaction on solids. (2) c) Explain the kinetics of parallel reaction (2) 35. a) Write briefly about Guoy-Chapman diffuse charge model of double layer (3) b) Calculate the mean ionic activity coefficient of 0.001molal K2SO4. (2) c) Calculate ionic strength for 0.2 molal solution of barium chloride. (2) 36. a) Derive Stern-Volmer equation. (3) b) Draw the jablonski diagram for fluorescence . (2) c) Calculate the quantum yield, if 1.3 moles of reactant undergo photochemical change on interacting with 0.13 einsteins of visible light. (2) 37. a) Give an example for photo-substitution reaction. (2) b) What is G-value? (2) c) Write about photo-assisted electrolysis of water. (3) 38. a) How to study fast reaction using pressure jump method. (3)

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Q9/15D/04-15 b) How dielectric constant affect the rate of reactions in solution. (2) c) What is collision frequency? (2) 39. a) What is meant by elastic and inelastic collisions? (2) b) Write the rate equation for H2-Cl2 and H2-Br2 photochemical reactions. (2) c) A sample of gaseous HI was irradiated by light of wavelength 260 nm, when 400 J of energy was found to decompose 2.1 X 10-3 mole of HI. Calculate the quantum yield of HI. (3) II. Fill up the blanks III. Match the following SECTION – B (10X2=20) Answer any TEN Questions

SECTION - C (5X7=35) Answer any FIVE Questions

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