CHE-2105 Spectroscopy-I Midsem Past Paper Feb 2021 PDF
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Uploaded by Deleted User
2021
The Maharaja Sayajirao University of Baroda
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This is a past paper for a midsemester exam in Spectroscopy-I (CHE-2105) from The Maharaja Sayajirao University of Baroda, 2021. The paper includes questions about chemical shift, NMR, crystal structures, and proper illustrations for solving the exercises. Suitable for undergraduate chemistry students.
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The Maharaja Sayajirao University of Baroda M.Sc.Part-I Mid Semester Examination Paper –V CHE – 2105 Spectroscopy-I Date :27.02.2021, Saturday Time:...
The Maharaja Sayajirao University of Baroda M.Sc.Part-I Mid Semester Examination Paper –V CHE – 2105 Spectroscopy-I Date :27.02.2021, Saturday Time: 10.00a.m. – 11.00a.m. Q.1 A. Identify generators in the following molecules: (i) S8 (sulphur) (iii) 2,3,6,7- tetrabromonaphthalee, (ii) BrF5 (iv) cyclohexane (boat form) B. Explain all improper rotations in IF7 with proper illustrations and identify all new operations. Q.2 A. Explain the non-axial point groups with appropriate examples. B. Identify all planes of symmetry in the cubic cell of CsCl. C. What are the generalized matrices for Cn and Sn operations? Use these and workout the matrices for C4 and S4 operations. Q.3 A Answer in brief. 1 Give Boltzman’s equation. How is it helpful in NMR? 2 The energy of each level in NMR is calculated by which formula? 3 For 400 MHz radiofrequency instrument how much magnetic field must be applied for 1H NMR? 4 What is range of Chemical shift for proton and for 13 C? B Answer (ANY TWO) 1 What is Chemical shift? Why is it independent of magnetic field? 2 Which are different types of relaxation processes? Explain. 3 Give an equation for precessional frequency with proper explaination Q.4 Answer all the questions a. A first order reflection from 222 planes of a cubic crystal was observed at an angle θ of Cu-K X-ray source (= 154pm)were used. What’s length of the side of the unit cell? (Given sinθ = 0.194). b. Number 7, 15 and _____ (any number) are called systematic absence. c. In the equation F(hkl) = f[1 + (-1)h+k+l], the condition for allowed diffraction will be when h+k+l = ? a. Odd b. even c. both odd or even d. none d. Draw Miller plane -401 in a cubic system. OR Powder sample XRD is a plot of -------- (X-axis) vs. _____ (Y-axis) e. What’s the difference between the structure factor ad scattering factor? f. These are hkl planes of a powder sample. Identify the type of structure. 111, 123, 222, 131, 242, 441, 352
