BSc Chemistry SEM V 2019 20 Oct 2019-20 CHEMISTRY PHYSICAL CHEMISTRY 15.10.19 Question Paper - Mumbai University | munotes

Questions asked in this paper

• (2) Figures to the right indicate full marks

1. Q1 Answer the following (any four)
   • A. Define dipole moment. Explain how dipole moment is useful in deciding 5
   • B. Derive expression for the wave numbers of line in the rotational spectrum ofa
   • C. What is a vibrational-rotational spectrum? Write any four characteristics of vibrational — rotational spectrum of a diatomic molecule 5
   • D. What are the three kinds of scattered beams of radiation in Raman spectrum? Explain the quantum theory of Raman spectra 5
   • E. The frequency separation of successive lines in the rotational spectrum of "HCl is 1.09 x while that of *H is 2.12 x Calculate isotopic mass of *H A substance was irradiated with visible radiation of wavelength 5 x (5) first stokes line appeared at 6 x Calculate the Raman shift and energy change for the transition Q?2. Answer the following (any four) 5
   • A. Define molal elevation constant. 5
   • 0.75g of solute was dissolved in 90g of benzene at 298K. The solution had a boiling higher than that of benzene. If benzene is calculate the molar mass of the solute
   • B. State Raoult’s law. Describe the Ostwald and Walker’s method to determine vapour pressure 5
   • C. Derive thermodynamically the relation between the freezing point depression of adilute of non-volatile solute and the mole fraction of the 5
   • D. What is reverse osmosis? Give its applications (any two) 5
   • E. Explain the Lindeman’s unimolecular theory of reaction rate. With the help of suitable diagram explain flash photolys is technique for (5) studying kinetics of fast reactions 5
2. Q3 Answer the following (any four)
   • A. Explain the construction, principle and working of Geiger muller counter. 5
   • B. Discuss the use of radioisotope as tracers in Photosynthesis and hydrolysis of — 5
   • C. Discuss the factors controlling nuclear fission process. 5
   • D. What is a nuclear power reactor? Explain the basic components of a power 5
   • E. Calculate the Q value and threshold energy of the following nuclear reactions Define half life period. A wooden chair freshly cut tree gives 3.8 and (5)
   • 7.6 counts of carbon whose half life time is 5760 years. Calculate the age of the wooden chair
3. Q4 Answer the following (any four)
   • A. What is electrophoresis? How it is studied experimentally? 5
   • B. Explain Helmholtz and Stern’s concept of electrical double layer. 5
   • C. Give an account of colloidal electrolytes. 5
   • D. Define : adsorbate adsorbent. Assuming that the adsorption of hydrogen gas forms a complete monolayer on the surface of charcoal, the volume of hydrogen reduced to S.T.P. was found to be per gm of the adsorbent. Calculate the surface area of adsorbent if area occupied by one hydrogen molecule is 15.8 X m? 5
   • E. Discuss any two methods by which colloids acquire electric charge. 5
   • F. Give application of surfactants in. 1) food industry pesticide formulation 5
   • A. Fill in the blanks with the correct option provided (any five) 5
   • 1. The dipole moment of HCI molecule is ------------ HF molecule
   • (a) greater than (b) lesser than (c) same as
   • 2. The molecular energies can be arranged as
   • 3. Raman shift is ----------------- for stokes line
   • 4. Scissoring vibrations are
   • (a) In plane vibration. (b) out of plane vibrations coupled
   • 5. A linear molecule like XeF2 will show--------------- vibrations
   • 6. UV — Vis are associated with--------------------------transitions
   • 7. Rayleigh scattering takes place when
   • 8. The unit for moment of inertia is B State whether the statement is TRUE or FALSE (any five). (5)
   • 1. A semipermeable membrane is permeable to solute molecules
   • 2. According to Raoult’s law relative lowering of vapour pressure for a solution is equal to mole fraction of solute
   • 3. For slow reactions probability factor P<1
   • 4. Addition of a non-volatile solute to a solvent will lead to an increase in
   • 5. Liquids with weak intermolecular forces are less volatile
   • 6. The rate of most of the reactions increase by factor of two for 10 degree rise in
   • 7. According to collision theory, the colliding molecules possess. translational C Match the following (any five) (5)
   • a. not affected by magnetic field
   • 2. Stellar bodies b. reaction proceeds at steady rate
   • c. minimum energy for reaction to proceed response from the counter D State whether the statement is TRUE or FALSE (any five). (5)
   • 1. Lyophilic sols are less. stable than lyophobic sols
   • 2. Langmuir’s isotherm fails at high pressure
   • 3. Charcoal is a good adsorbent for permanent gases
   • 4. Fog colloidal system of liquid in gas
   • 5. The movement of dispersion medium under the influence of an electric field is
   • 6. Chemisorption is an irreversible process Gel is a system in which liquid is a dispersed phase and solid is the dispersion

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