3*l?*fk* Sneqille-l NATIONAL INSTITUTE OF TECHNOLOGY, KI]RUKSHETRA END SEMESTER EXAMINATIONS, NOVEMBER/DECEMBER 2012 Programme: Subject: Course No.: Time allowed: 3 Hours Roll No. B. Tech. I Semester Chemistry-I CHT-I05 (Common with CHT-101and CHE-I01) Maximum marks: 50 Note: (1) (2) Unless stated otherwise, the Symbols have their usual meanings in context with the Subject. Assume suitably and state additional data required, if any. Before starling to write the solutions, the Candidates are mandatorily required to check the Question paper for "ny di..r"puncy ancl also ensure that they have been delivered the Question Paper of right Course No. and right Subject title. Attempt any five questions. All questions carry equal marks. Justify yor. urrr*ir(s) with suitable example(s)/chemical reaction(s)/neat, cleaned and labeled diagram(s), wherever applicable. (3) You are mandatorily required to write your Section on the top corner (RHS) of your Answer Sheet. (4) The question paper consists ofeight questions and is printed on both the sides. i (a) What'are second order reactions? Mention their two salient characteristics. Derive an expression for the velocity constant (k) of a second order reaction when the concentrations of both the reactants are different 6 (b) The rate constants of a second order reaction are 5.70 x l0-5 dm3 mol-' s-r and 1.64 x 10-4 dm3 mol I s-' at25'C and 40 "C respectively. Calculate the activation energy (E ) and Arrhenius pre- 4 exponential factor (l). II (a) What are reversible electrodes? How is the calomel electrode represented? Under what condition does the chloride ions concentration increase in the calomel electrode? OR Calculate the pH of the acidic solution in the following electrochemical cell: Hg, Hg2Cl2(s); fCt (saturated solution) ll H. lunknown concentration); Q, QHz, Pt' iftie values for the EMF of the above cell, Eo"u1o*"1 and Eo6{a,aq, are 0.26, 0.24 and0.70 metals (with the exception of noble metals) theory of wet corrosion of iron with the 6 4 respectively at 25 'C). (b) What is meant by corrosion of metals? Why do the undergo corrosion? Explain the electrochemical absorption of oxygen. III (a) State and explain the photochemical reactions and the reverse of photochemical reactions with suitable examples. Discuss any two points of differences between the photochemical and the dark 3 reactions. (b) Define the term spin multiplicity. With the help of a Jablonski diagram, explain the phenomena of fluorescence, phosphorescence, internal conversion, inter system crossing, radiative and non- radiative transitions. 7 IV (a) State and explain the following terms (any five): Phase, component, degrees of freedom, metastable equlibrium, transition temperature and enatiotropism. OR . Discuss the XRD method used for the.characterizalion of a given nano material. 5 Rest of the qyestions ure orinted on the bu?k of this sheet,..