Download SGBAU BSc 2019 Summer 5th Sem Cheistry Question Paper

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B.Sc. (Part—III) Semester—V Examination

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Time : Three Hours] [Maximum Marks : 80

Note :— (1) Question No. 1 is compulsory.
(2) Solve ONE question from each unit.
(3) Draw diagrams and give equations wherever necessary.

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1. (a) Fill in the blanks :
   1. The ligand that has four donor atoms for bonding is called __________
   2. Pyridine is __________ membered heterocyclic compound.
   3. A chromogen without __________ can never act as a dye.
   4. The reactions taking place in presence of light are called __________ reactions. 2

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2. (b) Select the correct alternative :
   1. Which of the following complex ion has highest crystal field splitting A value :
      (a) [Co(H₂O)₆]³⁺ (b) [Ni(H₂O)₆]²⁺
      (c) [Rh(NH₃)₆]³⁺ (d) [Ir(NH₃)₆]³⁺
   2. Tea tree oil can be used as :
      

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      (a) Insecticide (b) Herbicide
      (c) Fungicide (d) Rodenticide
   3. Photosynthesis of carbohydrates in plants from CO₂ and H₂O is example of :
      (a) Fluorescence (b) Phosphorescence
      (c) Photosensitized reactions (d) Dark reaction

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   4. Which of the following molecule shows highest force constant ?
      (a) C≡C (b) C-C
      (c) C=C (d) C-H
3. (c) Answer in one sentence each :
   1. What is coordination number ?

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   2. What is Laporte orbital selection rule ?
   3. What is Chichibabin reaction ?
   4. Define quantum yield. 4

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2. (a) Discuss geometrical isomerism exhibited by [Ma₂b₂] and [M(AA)₂b₂] complexes. 4
   (b) Discuss optical isomerism exhibited by [Mabcd] and [M(AA)₃] complexes. 4
   (c) Explain the following terms with suitable examples :
   (i) Effective atomic number
   (ii) Ligand. 4
   

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   OR
3. (p) Discuss Sidgwick’s electronics interpretation of co-ordination complexes. 4
   (q) Calculate EAN in the following
   (i) [Fe(CN)₆]⁴⁻
   (ii) [Cr(NH₃)₆]³⁺. 4
   

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   (r) On the basis of VBT discuss structure of [Co(NH₃)₆]³⁺. 4

UNIT—II

4. (a) Write different postulates of crystal field theory. 4
   (b) Explain Russell-Saunders (L-S) Coupling Scheme. 4
   (c) Calculate CFSE for [Cr(H₂O)₆]²⁺ High Spin Complex if Δ₀ = 13900 cm⁻¹ and P = 23500 cm⁻¹. 4
   

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   OR
5. (p) Explain crystal field splitting of d orbitals in octahedral complexes. 4
   (q) Discuss Orgel diagram for d¹ and d⁹ Octahedral complexes. 4
   (r) Write different types of absorption spectra. 4

UNIT—III

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6. (a) Write method of synthesis of pyrrole from :
   (i) Succinimide
   (ii) Furan. 4
   (b) Discuss orientation of nucleophilic substitution in Pyridine. 4
   (c) How will you prepare Ethane and 1-Butene from methyl magnesium bromide. 4
   

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   OR
7. (p) Describe acidic and basic nature of pyrrole. 4
   (q) Write synthesis of methyl lithium and how it reacts with (i) water (ii) formaldehyde. 4
   (r) How will you convert pyridine to the following :
   (i) 3-nitropyridine
   

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   (ii) Pyridine 3-sulphonic acid ? 4

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8. (a) Give preparation and uses of methyl orange. 4
   (b) Describe synthesis and uses of phenylbutazone. 4
   (c) Give method of preparation of Thiram. 4
   

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   OR
9. (p) Give the classification of dyes on the basis of their mode of application. 4
   (q) Write synthesis and uses of chloroquine. 4
   (r) Give method of synthesis of Malathion and its uses. 4

UNIT—V

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10. (a) Give statement of Lambert’s law and derive its equation. 4
    (b) Explain phenomena of fluorescence and phosphorescence with the help of Jablonski diagram. 4
    (c) A substance when dissolved in water at 10⁻⁴ M concentration absorbs 10% of an incident radiation in a path of 1 cm length. What should be the concentration of the solution in order to absorb 90% of the same incident radiation ? 4
    OR
11. (p) Explain kinetics of photochemical decomposition of HI. 4
    

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    (q) Write difference between thermal and photochemical reactions. 4
    (r) Light of intensity 3.2 x 10⁻⁶ einstein/sec falls on the surface of a crystal whose absorption coefficient is 3 x 10⁴ cm⁻¹ at the certain wavelength of light. Calculate the intensity of light at a depth of 100Å below the surface of the crystal. 4

UNIT—VI

12. (a) Explain energy level diagram for a simple harmonic oscillator. 4
    (b) Explain rotational Raman spectrum of diatomic molecule. 4
    

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    (c) The pure rotational spectrum of gaseous HCl contains a series of equally spaced lines separated by 20.80 cm⁻¹. Calculate the internuclear distance of the molecule. The atomic masses of H and Cl are 1.673 x 10⁻²⁷ kg and 58.06 x 10⁻²⁷ kg respectively. (h = 6.626 x 10⁻³⁴ JS). 4
    OR
13. (p) What is electromagnetic radiation ? Give its different parameters. 4
    (q) Derive an expression for moment of inertia of diatomic molecule. 4
    (r) Calculate rotational and vibrational degree of freedom for CO₂ and H₂O. 4

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