TYBSc Chemistry Sem 6 Physical Chemistry Question Paper PDF 2026 - Mumbai University | munotes

Questions asked in this paper

• (2). Figures to the right indicate full marks

1. Q1 Attempt any three of the following:
   • (A) Derive an expression for wave number of P-branch and R-branch lines in a vibrational 5 rotational spectrum of a diatomic molecule The equilibrium internuclear distance in the molecule of HBr is 142.0 pm. Calculate 5 the frequency separation between successive lines in pure rotational spectrum in
   • (C) Calculate the number of modes of vibration in the molecule of CO, using appropriate 5 expression, draw them. Giving reason, predict which modes are IR active and which one/s are Raman active
   • (D) The vibrational frequency of CO molecule is s? Assuming vibrations 5 to be harmonic, Calculate (i) vibrational frequency for the molecule in (ii) the force constant of the bond
   • (E) Derive the expression for moment of inertia of a diatomic molecule with m, and m, separated by internuclear distance
   • (F) Answer the following:
   • (a) Define dipole moment. 1
   • (b) Why some molecules have zero dipole moment where as others possess 2,
   • (c) Explain the geometry of BF, and NH, on basis of dipole moment. 2
2. Q2 Answer any three of the following:
   • (A) Describe the Tafel's theory for hydrogen overvoltage. 5
   • (B) The overvoltage of hydrogen on a certain cathode is 0.34 V. Calculate the minimum 5 voltage that must be applied to evolve hydrogen on this cathode from a solution From the above equation, derive the expression for the wave y in a clamped string using boundary condition. Also draw the wave function y,, for and
   • (D) Answer the following:
   • (p) Heisenberg's uncertainty Principle. Give its significance
   • (q) the characteristics of wave function 3
   • (E) Differentiate between matter waves and electromagnetic waves. 2 The velocity of an electron in motion is ms”. Calculate 3
   • (i) The kinetic energy of electron
   • (ii) The wavelength of the matter wave associated with the electron
   • (F) State the expression for time independent schrodinger wave equation for the particle 5 mass 'm' moving in three dimension and explain the terms involved
3. Q3 Answer any three of the following:
   • (A) Describe with the help of neat labelled diagram, the stop flow method used to 5 fast reactions. Give two examples of fast reactions
   • (B) Explain the method of electrolysis of water to produce hydrogen. 5
   • (C) Explain the low resolution NMR spectrum of methanol and ethanol. 5
   • (D) (a) the expression for collision frequency of a bimolecular reaction 2 and identify the terms involved
   • (b) Give any three drawbacks of collision theory of reaction rates. 3
   • (E) Explain the principle, construction and working of silicon solar cell. 5
   • (F) Answer the following with respect to NMR spectroscopy
   • (a) State the reasons for using tetramethylsilane as internal standard. 3
   • (b) What is meant by spin-lattice relaxation? 2
4. Q4 Answer any three of the following:
   • (A) What are tracers? Explain the use of tracer in studying reaction mechanism with 5 the help of a suitable example
   • (B) What is meant by nuclear transmutation and artificial radioactivity? Differentiate 5 between the two
   • (C) Explain the use of moderator, coolant, reflector, fuel and contro] rods in a nuclear 5
   • (D) Explain the use of phosphors and the working of photomultiplier tube in scintillation counter used to detect and measure radioactivity. ~ 5
   • (E) The half-life of is 7.1x10* years and its daughter element is with half life 24.75 hour. Find the weight of in equilibrium with one gram
   • (F) Find the Q Value and threshold energy of the following reaction State True False for the following statements Rule of mutual exclusion is applicable to linear molecule with centre of symmetry
   • (b) The energy difference between any two successive vibrational energy levels is constant
   • (c) Dipole moment is a scalar quantity
   • (d) In-plane bending vibrations are classified as rocking and wagging
   • (A) Choose the correct answer:
   • (p) For stokes in Raman (1) A, (ii)
   • (q) For pure rotational spectra
   • (r) The vibrational degree of freedom for non-linear molecule of H,O is
   • (s) Rotational spectra is observed for
   • (B) State true or false for the following statements
   • (a) The phenomenon like Black body radiation is explained by taking into account the wave nature of light
   • (b) The mathematical expression of Tafel's equation is n=a-b
   • (c) The de Broglie relation shows that the wavelength is directly proportional to the momentum of a particle Electroplating reduces corrosion of metal the correct answer
   • (p) Hamiltonian operator is : (q) If the operator operates on the function sin 3x, the eigen value is
   • (r) The deposition potential is given by
   • (s) Hydrogen overvoltage is also called as
   • (C) State true of false for the following statements
   • (a) According to collision theory of reaction rates, the rate of reaction is proportional to the total number of collisions per em’ per second
   • (b) A fuel cell is a device that combines hydrogen and carbon-di-oxide to produce electricity and water
   • (c) In NMR spectroscopy, resonance refers to equal magnitude of absorbed and
   • (d) FeS, is used as a cathode in lithium - ion cell
   • (C) Choose the correct answer
   • (p) The most likely alternative to fossil fuel for clean energy in future is
   • (q) The nuclear spin of
   • (r) At low pressure many gaseous reactions are
   • (s) A semiconductor with excess holes is called
   • (D) State true or false for the following statements
   • (a) Threshold energy for nuclear reactions is calculated for exoergic reactions
   • (b) Energised projectiles are used to induce artificial radioactivity.
   • (c) “*U is a fertile material
   • (D) Choose the correct
   • (p) The examples of fissile material is given by
   • (q) One curie activity is defined as
   • (r) Radioactive equilibrium is
   • (i) irreversible
   • (ii) affected by temperature and pressure
   • (iii) reached in very short time as compared to chemical equilibrium

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