Loyola College M.Sc. Chemistry April 2009 Electrochemistry Question Paper PDF Download

        LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

M.Sc. DEGREE EXAMINATION – CHEMISTRY

WD 47

FOURTH SEMESTER – April 2009

CH 4808 / 4805 / 4803 – ELECTROCHEMISTRY

 

 

 

Date & Time: 21/04/2009 / 9:00 – 12:00  Dept. No.                                                     Max. : 100 Marks

 

 

PartA (20 Marks)

Answer ALL questions (10 x 2 = 20)

  1. Calculate the ionic strength of a solution obtained by mixing 50 ml of 0.02 M
    Na2SO4 and 50 ml of 0.02 M cerium (III) sulphate solutions.
  2. Mention the factors affecting the thickness of the ionic atmosphere of an electrolytic solution.
  3. E°red of Au+/Au is 1.68 V, E°red Au3+/Au is 1.50 V. Calculate E°oxi  of Au+/Au3+
    at 25°
  4. Calculate the zeta potential of a colloidal particle in aqueous solution that has an
    electrophoretic mobility of 1.1   10-8 m2 s-1 V-1.  The coefficient of viscosity of water  is 8.91 x 10-4 kg m-1 s-1 and  Î = 78.3.
  5. What is ‘Dorn Effect’?
  6. Draw the general pattern of the plot of current density vs overvoltage for an electrode having symmetry factor 0.75.
  7. What do you mean by the high field approximation of the Butler-Volmer equation.
  8. The diffusion current of a certain metal ion at  3 × 10-2 mM is 3.3µA calculate its diffusion current at 6.9 × 10-2 mM concentration.
  9. Bring out the difference between voltammetry and polarography.
  10. Differentiate between half wave and standard reduction potentials.

Part-B (40 Marks)

Answer ANY EIGHT questions (8 x 5 = 40)

  1. Deduce Lippmann’s equation and mention its significance.
  2. Explain the influence of electrolytes on electrokinetic effects.
  3. The thermodynamic dissociation constant of a weak acid (HA) at 25°C is 2 10-5.
    What is the degree of dissociation of 0.1 M acid in 0.01 M KNO3 (aq) solution?
  4. Calculate Kh for NH4Cl if the EMF of the cell.

Pt½H2(1 atm)½NH4Cl(0.2M) ½½ KCl(1M)½Hg2Cl2½Hg

at 25° C is 0.574 V and E°red of calomel electrode is 0.28 V.

  1. Determine the potential due to ionic atmosphere around cation at 25° C for
    10-3M CaCl2(aq)  if Î0 = 8.854  ´ 10-12 C2J-1m-1 and dielectric constant of water is
    3.
  2. Explain Wien’s effect and its importance in the study of strong electrolytes.
  3. Electrolysis of a solution of Cu2+ produces 16 mg of Cu in 2 minutes. Calculate the rate of the reaction.

 

  1. What do you mean by non polarisable electrode? How is it related to its current density?
  2. Calculate the current density across an electrode (β = 0.45) at an applied potential of 0.23V if its equilibrium potential is 0.09V
  3. Explain migration and diffusion currents. Which current is significant in poloragraphy? How is it achieved?
  4. The dissolution of iron follows the following mechanism:

Fe  +  H2O         FeOH      +  H+ +   e ;  Eq Const K1……….……1

FeOH                  FeOH+    +   e–                ;   Eq Const K2……….…….2

FeOH+   + H+       Fe2+  + H2O              ;  Eq Const K3 …………….3

Determine its transfer coefficients if step-2 is the rate determining step.

  1. Explain the electrochemical reduction of a typical aromatic ketone.

Part-C (40 Marks)

Answer ANY FOUR questions (4 x 10 = 40)

  1. What is the need for a model on electrical double layer? Explain Helmohlltz-Perrin model and mention its defects.                                         (3 + 5 + 2)
  2. (a) Mention the assumptions of Debye-Huckel theory and explain any one
    application of Debye-Huckel limiting law equation.                  (3 + 4)

(b) What is the need to modify the limiting law equation.            (3)

  1. Explain any two of the following:
  • Relaxation effect
  • Electroosmosis
  • Gouy-Chap mann model of electrical double layer
  • van’t Hoff factor.
  1. Derive the relation between current density and applied potential for an electrode undergoing multistep multi electron reaction
  2. Define limiting current. Derive an expression for it relating to concentration on the basis of the concept of concentration polarization.
  3. Explain the following with suitable examples and figures.
  • Amperometric titrations
  • Electrodes as anodic rectifiers
  • Three electrode system.

 

Go To Main page

Latest Govt Job & Exam Updates:

View Full List ...

© Copyright Entrance India - Engineering and Medical Entrance Exams in India | Website Maintained by Firewall Firm - IT Monteur