Download SGBAU BSc 2019 Summer 2nd Sem Chemistry Question Paper

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B.Sc. (Part-I) Semester—II Examination

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CHEMISTRY

Time : Three Hours] [Maximum Marks : 80

Note :— (1) All questions are compulsory.

(2) Question No. 1 carries 8 marks, while each of the remaining six questions carries 12 marks.

(3) Draw diagram and write equations wherever necessary.

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(4) Use of scientific calculator is allowed.

1. (A) Fill in the blanks :
   1. The total number of atoms or molecules whose concentration determines the rate of a reaction is called as ___________.
   2. The type of hybridization in CIF₃ molecule is ___________.
   3. The unit of rate constant for a second order reaction is ___________.
   4. In chlorobenzene, chlorine atom is bonded to hybridized carbon atom of the benzene ring.

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   2

2. (B) Choose the correct alternative :
   1. The outer shell electronic configuration of 17^th (VII A) group elements is :
      1. ns² np⁵
      2. ns² np⁴
      3. ns²np³

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      4. ns¹ np²
   2. Dihydric alcohols are known as :
      1. diols
      2. triol
      3. geraniols

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      4. none of the above
   3. The shape of PCl₅ molecule is :
      1. V shape
      2. Trigonal bipyramidal
      3. T shape

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      4. Tetrahedral
   4. The dipole moment of CO₂ molecules is :
      1. +ve
      2. zero
      3. +ve and -ve

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      4. none of these

   4x½=2

3. (C) Answer in one sentence
   1. What is pseudo unimolecular reaction ?

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   2. What are epoxides ?
   3. What are non polar solvents ?
   4. What is the IUPAC name of CH₃-CH₂-CH₂-O-CH₂-CH₃ ?

   1x4=4

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UNIT—I

2. (A) Explain LUX-Flood concept of acid and base with suitable example. 4
3. (B) What is Polarization ? Explain the Polarization of the anion by the cation. 4
4. (C) What is SHAB Principle ? How is it useful to predict the stability of complex ? 4

OR

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3. (P) Discuss the structure of HF₂^- molecule. 4
4. (Q) How charge and size of a cation affects Polarisation of anion ? Explain. 4
5. (R) Explain :
   1. CaCl₂ is readily soluble but AgCl is sparingly soluble in water. 2
   2. Melting point of CaCl₂ is higher than that of BaCl₂. 2

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UNIT—II

4. (A) Write the electronic configuration of oxygen family elements. 4
5. (B) Explain the structure of XeO₃ molecule. 4
6. (C) How are solvents classified on the basis of proton donating and accepting ability ? 4

OR

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5. (P) Discuss structure and bonding in IF₇ molecule. 4
6. (Q) Explain the structure of XeF₄ molecule. 4
7. (R) Write any two reactions of liquid ammonia. 4

UNIT—III

6. (A) How will you prepare Benzyl chloride from :
   1. Toluene

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   2. Benzyl alcohol ? 4
7. (B) How will you prepare :
   1. Ethylene glycol from ethylene ?
   2. Trinitro glycerol from glycerol ? 4

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8. (C) How will you obtain glycerol form propene by chlorination ? 4

OR

7. (P) Explain the mechanism of SN¹ reaction. 4
8. (Q) Compare the reactivity of chlorobenzene and benzyl chloride towards the nucleophilic substitution reaction. 4
9. (R) What happens when :
   1. Allyl chloride reacts with Aq. KOH ?

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   2. Acetylene gas passed through dil HCl at 433K in presence of Hg₂Cl₂ ? 4

UNIT—IV

8. (A) Give the following reaction of Phenol :
   1. Kolbe's Reaction
   2. Fries Rearrangement. 4

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9. (B) Explain the ring opening reaction catalysed by acid. 4
10. (C) What is action of cold and hot HI on diethyl ether ? 4

OR

9. (P) What are Phenols ? How Phenol is prepared from cumene ? 4

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10. (Q) Complete the following :
    1. CH₂=CH₂+ RCO₃H ? ?
    2. CH₃-CH₂-Br + CH₃-CH₂-ONa ? ? 4
11. (R) How will you prepare :
    1. Diethyl ether from ethyl alcohol
    2. Styrene oxide from styrene ? 4

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UNIT—V

10. (A) What are paramagnetic substance ? Give their characteristics. 4
11. (B) Calculate number of unpaired electrons when magnetic moment is 4.9 B.M. 4
12. (C) Discuss any two applications of dipole moment. 4

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OR

11. (P) Describe the refraction method for the determination of dipole moment. 4
12. (Q) Discuss Gouy's balance method for determination of molar magnetic susceptibility. 4
13. (R) If the magnetic substance contains three unpaired electrons, calculate its magnetic moment. 4

12. (A) Define :
    1. Pseudo First Order Reaction

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    2. Molecularity. 4
13. (B) Define zero order reaction and give one example. What is the unit of zero order rate constant ? 4
14. (C) Describe the graphical method for determination of order of reaction. 4

OR

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13. (P) Describe Van’t Hoff's differential method for the determination of order of reaction. 4
14. (Q) Define :
    1. Order of reaction
    2. Activation energy. 4
15. (R) For a given reaction at 25°C, rate constant doubles when temperature is increased by 10°C calculate the energy of activation for this reaction. Given : [R = 8.314Jk^-1mol^-1]. 4

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