Catalysis, Photocatalysis, Application of Reagents in Organic Synthesis and Statistical Thermodynamics — DU Physical Science courses pertaining to Chemistry Previous Year Question Papers

APPLICATION OF REAGENTS IN ORGANIC SYNTHESIS AND STATISTICAL This question paper comprises three sections, each carrying 30 marks : Section A : Inorganic Chemistry Section B : Organic Chemistry Section C : Physical Chemistry Attempt each section on a separate answer sheet, clearly marking the section (A/B/C) at the top of each sheet. Attempt six questions in total, selecting two questions from each section. (INORGANIC CHEMISTRY) Explain the general principles of catalysis and discuss the properties of catalysts. Write short notes any two of the following: (ii) Turnover frequency (iii) Turnover number (c) What is band gap? Explain its significance in photocatalysis. (5,5,5) 2. (a) Explain the importance of catalysis in eco-friendly energy solutions. (b) Explain the catalytic cycle, and mechanism of alkene hydrogenation using Wilkinson’s catalyst. (c) Explain the Wacker-Smith synthesis of aldehydes along with its catalytic cycle and mechanism. (d) Discuss the importance of UV-visible light filters in photocatalytic studies. 3. (a) Discuss the role of photocatalysis in hydrogen production and CO2 (b) Describe the polymerisation of ethene using Ziegler-Natta catalyst with suitable mechanism. (c) Differentiate between homogeneous and heterogeneous catalysis. (5,5,5) (ORGANIC CHEMISTRY) 4. Write short notes on the following (any five) : (a) (b) (c) Discuss the synthesis and application of crown ethers. Give the synthetic application of borane and alkylboranes in organic synthesis. Discuss the following : KMNO4 Oxidation ii) Barton Reaction. (5,5,5) 5. Write short notes on the following (any five) : (a) Tallium nitrate (b) Organo Zinc reagent (f) Grignard reagent (3,3,3,3,3) 6. (a) Complete the following reactions (any six) : (1×1.5) (b) Give the mechanism of the reactions : (any two) (PHYSICAL CHEMISTRY) Show that for a system of particles obeying Maxwell-Boltzmann Statistics, the most probable distribution is given by the expression: where symbols have their usual meaning. (b) (c) Given a system of 5 weakly interacting distinguishable particles which can occupy any of the three energy levels of energy 0,  and 2. Let the total energy of the system be 5. Find out all possible macrostates and their corresponding number of microstates. Starting from the definition of factorial, use an integral approximation to derive Stirling’s formula for lnN! (7,5,3) 8. (a) (b) (c) Using the quantum mechanical expression for the rotational energy of a diatomic molecule, derive the expression for the rotational partition function. What are the assumptions of Conventional transition state theory? Show how equilibrium constant of a gas phase reaction can be expressed in terms of partition functions of the involved species. What do you mean by an ensemble? Explain different types of ensembles.