Loyola College Electrochemistry Question Papers Download
Loyola College M.Sc. Chemistry Nov 2003 Electrochemistry Question Paper PDF Download
LOYOLA COLLEGE (AUTONOMOUS), CHENNAI –600 034
M.Sc., DEGREE EXAMINATION – CHEMISTRY
FOURTH SEMESTER – NOVEMBER 2003
CH – 4803/1020 – ELECTRO CHEMISTRY
01112003 Max:100 marks
1.00 – 4.00
PART – A (10X2=20 marks)
Answer ALL questions.
 The limiting molar conductance of OHis highest among the anions – Explain.
 Calculate the ionic strength of a mixture containing 20 mL of 0.1M lanthanum sulphate, 30 mL of 0.5 M magnesium nitrate and 50 mL of water.
 In case of alkali halides the deviation from Debye Huckel Onsager equation is more marked as the atomic weight increases – Explain.
 Calculate the limiting molar conductance of lanthanum ion if its mobility is 7.21 x 10^{8} m^{2} V^{1} S^{1}.
 Write Lippmann’s first equation and mention its importance.
 Draw the plot of current density vs applied potential for an electrolytic solution and hence indicate the discharge potential of an ion.
 Mention the electrical properties that influence the rate of an electrochemical reaction.
 Bring out the differences between symmetry factor and transfer coefficient.
 What do you mean by nonpolarisable electrode?
 Define exchange current density.
PART – B (8X5=40 marks)
Answer any EIGHT questions.
 Calculate the instability constant of the complex formed in the reaction
Cu^{+2} + 4 NH_{3} [Cu (NH_{3})_{4}]^{+2}
Given Cu^{+2} +2 Cu_{(s)} E^{o} = 0.337 V
[Cu (NH_{3})_{4}]^{2+} + 2 Cu_{(s) } + 4 NH_{3} E^{o} = 0.12 V.
 2 M lead nitrate solution freezes at 0.05^{o}C. Calculate its dissociation constant. Cryoscopic constant of water is 1.86 kg K mol^{1}.
 The dissociation constant of chloroacetic acid is 1 x 10^{4}. Will the degree of dissociation increase or decrease if 0.1 M KCl is added to 0.1 M chloro acetic acid?
 Write notes on electro kinetic phenomena.
 Discuss electrocapillary phenomena.
 How is the limiting molar conductance of acetic acid determined using Debye Huckel Onsager – equation?
 Compare the rates of reduction of Ag^{+}, at over voltages 0.1 and +0.1 V, which has a symmetry factor, = 0.5.
 Explain any one experimental method of determining the exchange current density.
 State Butler – volmer equation for one electron process. Derive Nernst equation from it.
 Determine the order of the reaction 2 H_{3}O^{+} + 2e 2 H_{2}O + H_{2} in acidic medium.
 Derive Tafel equation for cathodic process.
 Define half wave potential. Show that it is a constant characteristic of the electro active species.
PART – C (4X10=40 marks)
Answer any FOUR questions.
 State the postulates of Debye Huckel theory and derive an expression for Debye Huckel length.
 Derive Debye Huckel limiting law. How is it verified? Mention its applications.
 What are the features of Helmholtz Perrin model? What are its limitations? How are these overcome in Stern’s model?
 a) Derive the Butler – Volmer equation for a multistep electrochemical reaction.
 b) Explain the condition under which the above equation reduces to simpler Butler –
Volmer equation.
 a) A cathodic potential of 3V is applied to Cu^{2+} and Na^{+} solutions separately. Calculate
the over potential of the two electrodes.
 b) Explain any three applications of polarography.
 a) Obtain an expression for limiting current on the basis of concentration polarization.
 b) Write a note on
 Cyclic voltametry
 Amperometric titrations
Loyola College M.Sc. Chemistry April 2006 Electrochemistry Question Paper PDF Download
LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034
M.Sc. DEGREE EXAMINATION – CHEMISTRY

FOURTH SEMESTER – APRIL 2006
CH 4805/CH 4803 – ELECTROCHEMISTRY
Date & Time : 20042006/FORENOON Dept. No. Max. : 100 Marks
Part–A (20 Marks)
Answer ALL questions (10 x 2 = 20)
 Calculate the thickness of ionic atmosphere in 0.1M aqueous lanthanum sulphate.
 Compare the ionsolvent interaction of the following
 1M aq KCl
 1M aq Al_{2}(SO_{4})_{3}
 λ _{H+ }is the highest among cations in aqueous solution. Why?
 How is the capacitance related to the thickness of double layer in Helmholtz Perrin
model?
 What are surfactants? Give example.
 What do you mean by a polarisable electrode? State the condition for its ideal
polarisability.
 What is reaction resistance? Calculate its value of an electrode having equilibrium
current density 2 .08 μA cm.
 Nernst equation is a special case of ButlerVolmer equation.Explain.
 Determine whether Cu form 0.01 M Cu^{2+ }will be deposited or not.
( SRP : Cu^{2+}/ Cu = 0.34V )
 Obtain the relation between rate and current density of an electrochemical reaction
from Faraday’s laws.
PartB (40 Marks)
Answer any EIGHT questions (8 x 5 = 40)
 11. What are electro capillary curves? What is its importance?
 Derive an expression for the interfacial tension applying parallel plate condenser
model.
 Apply Born’s model to find out the energy of ion solvent interaction.
 14. Discuss the evidences for the existence of ionic atmosphere.
 15. The measured emf for the cell Ag, AgBr,KBr  Hg_{2}Br_{2}  Hg are 0.06839V at 25ºC
and 0.07048V at 30ºC. Write the reaction involved and calculate ∆H, ∆G and ∆S
for the reaction at 25ºC
 A 0.2m lead nitrate solution freezes at 0.10ºC. Calculate the dissociation constant
if K_{f} of water is 1.86 K molal^{1}
 Derive the ButlerVolmer equation for a one electron electrode process.
 18. Define transfer coefficient. How is it determined experimentally?
 19. The reversible potential and c.d of an electrode are 0.22 V and 7.2×10 ^{4} A cm^{2 }
^{ }respectively. Calculate the c.d across it at 0.74 V if it has 40% cathodic tendency.
 20. The tafel anodic and cathodic slopes of “applied potential vs logi ” of an
electrode process were found to be 0.04 & 0.12 respectively. Calculate the
ransfer coefficients.
 21. Explain the applications of Tafel equations.
 22. The exchange current density of Pt/Fe, Feis 2.5 mA cm. Calculate the
current density across the electrode at 25C maintained at 1V when [Fe] = 0.1
M and [Fe]= 0.2 M (SRP = 0.77IV, β = 0.58)
PartC (40 Marks)
Answer any FOUR questions (4 x 10 = 40)
 23. Discuss sterns model of double layer structure.
 24. Describe ‘Electrokinetic Phenomena’.
 25. Derive Debye Huckel limiting law. How is it verified?
 26. For the system Pt /Fe^{3+}, Fe^{2+} at 298K the i were measured as shown below:
(mV): 50 80 100 120 150 200
(mA cm) : 8.01 16.1 25.17 41 82.4 264
Evaluate i_{o} and β
 27. Consider the following mechanism for the deposition iron.
Fe^{2+ }+ H_{2}O FeOH^{+} + H^{+ }eq const K_{1} ……. (1)
^{ } FeOH^{+} + e FeOH eq const K_{2} ……. (2)
FeOH + H^{+ }+ e Fe + H_{2}O^{ }eq const K_{3}^{ }……. (3)
Derive the expression for rate if step2 is rds
 Discussion of Butler Volmer equation for different values of over potentials.
Loyola College M.Sc. Chemistry April 2007 Electrochemistry Question Paper PDF Download
LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

M.Sc. DEGREE EXAMINATION – CHEMISTRY
FOURTH SEMESTER – APRIL 2007
CH 4805 / CH 4808 – ELECTROCHEMISTRY
Date & Time: 18/04/2007 / 9:00 – 12:00 Dept. No. Max. : 100 Marks
PART – A
Answer ALL the questions (10 x 2 = 20 marks)
 The deviation from Debye Huckel Onsager equation is more marked as the atomic weight of alkali metal halide increases – Explain.
 Which of the following will have greater ion – ion interaction?
(i) 0.01 m KCl (ii) 0.01 m CuSO_{4}.
 and are 0.337 and 0.521V respectively. Is it easier to
oxidize cu to cu^{+} or cu to cu^{+2}?
 According to Stern’s model, how do ions congregate in solution?
 Define potential of zero charge.
 Derive the expression for the electrochemical reaction rate on the basis of Faraday’s laws of electrolysis.
 Define exchange current density of and electrode. How is it related to its polarisability?
 Indicate the potential range at which an electrode shows ohmic and non ohmic behaviours.
 Define transfer coefficient. How can it be determined experimentally?
 Define diffusion over potential. Explain how the concentration over potential can arise mainly due to diffusion.
PART – B
Answer any EIGHT questions (8 x 5 = 40 marks)
 Consider the cell, cd/cdcl_{2} . 2½ H_{2}O/Agcl_{(s)}/Ag_{(s)}. The emf of the cell at 15C is 0.67531and the temperature coefficient of emf is –0.00065 Vdeg^{1}. Calculate DG, DS and DH for the above cell reaction at 15^{o}C.
 Derive an expression for the Debye Huckel length.
 Determine the solubility of BaSO_{4} in (i) 0.1m BaCl_{2} and (ii) 0.1m KNO_{3}. K_{sp} of BaSO_{4} is 1 x 10^{10 }mol^{2} dm^{6}.
 Calculate the limiting molar conductance of lanthanum sulphate from the following data:
 What are electro capillary curves? How is it influenced by surfactants? Explain.
 Write notes on electroosmosis.
 The exchange current density, I_{o} of a certain electrode and its symmetry factor, b are 1.35 mA and 0.45. Calculate is cathodic current at an over potential of 300mV.
 Calculate the magnitude of the anodic Tafel slope of the plot of logi vs h for an electrode having its anodic transfer coefficient 1.5 at 298K.
 Calculate the minimum potential required for the discharge of Ag^{+} from its 1x 10^{3} M solution at 298K (The SRP of Ag^{+}/Ag system = 0.80V).
 The reduction of Fe^{2+} to Fe follows the following mechanism
Fe^{2+} + H_{2}O ⇄ FeOH^{+} + H^{+} eq conts K_{1} ….. (1)
FeOH + e ⇄ FeOH eq conts K_{2} ….. (2)
FeOH +H^{+} + e ⇄ Fe + H_{2}O eq conts K_{3} ….. (3)
Determine the following parameters if step2 is rds.
= ; ; n ; r ; and
 Discuss any five types over potential for an electrode system.
 State the following relation for polarography connecting
 EMF & current density
 Current density & concentration
Explain their applications.
PART – C
Answer any FOUR questions (4 x 10 = 40 marks)
 Derive Debye Huckel Onsager equation. How is it verified?
 Give an account of ‘Parallel Plate Consdensor Model’ to explain the double layer structure.
 Define ionion interaction. Derive an expression for ionion interaction interms of chemical potential.
 a) Derive the Butlervolrmer equation relating current and over potential for a
simple electrode system.
 b) Deduce Ohm’s law equation from the above relation.
 a) Explain the factor deciding electrode rectification?
 b) Discuss ButlerVolmer equation for different value of over potential.
 The electrochemical reduction of I to I proceeds by a three step mechanism viz., fast equilibrium dissociation of (i) I to I_{2} & I (ii) I_{2} to I (iii) followed by the slow reduction of the dissociated I atoms to I. Write the mechanism of the reaction and hence determine the transfer coefficient for the reaction.
Loyola College M.Sc. Chemistry April 2008 Electrochemistry Question Paper PDF Download
LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034
M.Sc. DEGREE EXAMINATION – CHEMISTRY

FOURTH SEMESTER – APRIL 2008
CH 4808 – ELECTROCHEMISTRY
Date : 210408 Dept. No. Max. : 100 Marks
Time : 9:00 – 12:00
PART A
Answer ALL questions (10 x 2 = 20 Marks)
 Calculate the thickness of the ionic atmosphere in 0.10M aqueous solution of
barium chloride at 298K. (Dielectric constant of H_{2}O at 298K = 78.6).
 Derive the expression for the rate of an electrode reaction using Faraday’s law.
 An electrolyte of the type A_{2}B_{3} is 85% ionized in 0.01M solution.
What is the value of Vant’ Hoff i factor?
 What is Wien effect?
 Write Lipmann equation and explain the terms.
 What are the factors which affect the symmetry factor in an electrode reaction?
 Explain the various factors which influence the zeta potential.
 What is meant by stoichiometric number?
 Removal of oxygen from analyte is very essential in polarographic analysis.Why?
 Write the expression for the charge transfer resistance in an electrode reaction
at low overpotential.
PART B
Answer any EIGHT questions (8 x 5 = 40 Marks)
 Discuss the Born model for ion solvent interactions.
 Account for the abnormal conductance of H_{3}O^{+} ion in protic solvents.
 Explain the electrokinetic phenomena on the basis of irreversible thermodynamics.
 Calculate the values of Debye Huckel Onsager constants A and B for methanol
at 298K. (For methanol ε =31.5 and η = 0.545 centipoise).
 Distinguish between polarisable and nonpolarisable electrodes with
suitable examples.
 Discuss the mechanism of electroreduction of nitrobenzene.
 Explain how electrophoretic and relaxation effects affect the mobility of
an ion in solution.
 What are the advantages of DME? Mention two of its disadvantages.
 What is zeta potential? How is it determined?
 Deduce Nernst equation from Butler – Volmer equation.
 Explain: Halfwave potential and Residual current
 Calculate the mean ionic activity coefficient in 0.01M aqueous solution of
potassium ferrocyanide at 298K using Debye – Huckel limiting law.
PART C
Answer any FOUR questions (4 x 10 = 40 Marks)
 Derive Debye Huckel Onsager equation. How is it verified?
What are its limitations?
 Discuss the Stern model of double layer structure.
How is it superior to other models?
25 a).Derive Butler – Volmer equation for a single step one electron transfer reaction.
 b) Discuss the high field and low field approximations of the above equation.
 a)Describe any two applications of polarography.
b)Calculate the maximum diffusion current in the polarographic reduction of Zn^{+2}
ions from a 3 x 10^{3} M solution with diffusion coefficient of 7.2 x 10^{6} cm^{2} s^{1}.
The capillary used in DME is such that it liberates 1.5 mg of Hg per second
with a drop time of 2 seconds.
 Discuss the use of Pourbaix diagram in understanding the thermodynamic stability
of iron at different pH values.
28 a).A 0.2m solution of lead nitrate freezes at 0.10^{o} C If K_{f } of water is 1.86 Kmolal^{1}
^{ } what is the degree of dissociation of lead nitrate in 0.20m solution?
b)Consider the following mechanism for the reduction of I_{3}^{ – } ion
Step 1 I_{3}^{– } I_{2 }+ I^{–}
^{–}
Step 2 I_{2 } _{ } 2 I
Step 3 2 (I + e^{– } → I^{–} )
Derive the rate equation for the reaction considering step 3 as the rate determining
step and explain how the electrochemical reaction orders establish the mechanism.
Loyola College M.Sc. Chemistry April 2008 Electrochemistry Question Paper PDF Download
LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

M.Sc. DEGREE EXAMINATION – CHEMISTRY
FOURTH SEMESTER – APRIL 2008
CH 4805 / 1020 – ELECTROCHEMISTRY
Date : 03/05/2008 Dept. No. Max. : 100 Marks
Time : 1:00 – 4:00
PART A
Answer ALL questions (10 ´ 2 = 20 Marks)
 Calculate the ionic strength in 0.01M potassium ferricyanide solution.
 Explain the significance of symmetry factor in an electrode reaction.
 How does electrophoretic effect affects the ionic mobility in a solution of strong electrolyte?
 Explain IHP and OHP at the electrode – electrolyte interface.
 What is meant by Lippmann potential?
 Explain concentration polarization.
 Vant Hoff ‘ i ‘ factor for AB_{2 }type electrolyte at a given concentration is 2.8. What is its percentage of ionization?
 Illustrate primary cell with an example.
 The solubility of mercurous chloride in water at 25^{o} C is 1.0 x 10^{5} mol dm^{3} . What is its K_{SP }value at the same temperature?
 What are surfactants? Give an example.
PART B
Answer any EIGHT questions (8 x 5 = 40 Marks)
11 State Debye – Huckel limiting law. How is verified?What is its limitation?
 Account for the abnormal mobilities of H_{3}O^{+ }and OH^{–} ions in aqueous solution.
 How is the solubility product of a sparingly soluble salt like AgCl is determined from EMF measurements?
 Deduce Nernst equation from Butler – Volmer equation.
 Write briefly on Helmholtz – Perrin model for an electrical double layer.
 Distinguish between polarisable and nonpolarisable electrodes with suitable examples.
 Explain the dependence of pH on corrosion using Pourbaix diagram.
 Write briefly on (i)Streaming potential (ii)Sedimentation potential
 Calculate the thickness of ionic atmosphere in 0.10M calcium chloride solution in water at 27^{o }C . (Dielectric constant of water is 78.6)
 Write a note on H_{2 }– O_{2 }fuel cell.
 Explain Debye Falkenhagen effect.
PART C
Answer any FOUR questions ( 4 x 10 = 40 Marks)
 Derive Butler – Volmer equation for a single step single electron transfer reaction and explain the low and high field approximations.
 Discuss the Stern model for the electrode – electrolyte interface.
 Derive the Debye – Huckel – Onsager equation .
 a)Explain the amperometric method of estimation of silver nitrate.
b)What are electrocpillary curves?Explain its significance.
 a)How does hydrogen over voltage arise?
b)Describe any two methods employed for the prevention of corrosion.
27.a)The equilibrium exchange current density for the reaction
H^{+ } + e ^{–} → H_{2 }
on nickel at 25^{o} C is 1.00 x 10^{5 } A cm^{2} . What current density would be
necessary to attain a cverpotential of 0.1V ? (α = 0.5).
b)For Weston standard cell at 298K emf is 1.01032 V and temperature
coefficient of emf of the cell is 5.00 x 10^{5 } VK^{1 } . Calculate ∆ G , ∆H
and ∆ S of the cell reaction.
Loyola College M.Sc. Chemistry April 2009 Electrochemistry Question Paper PDF Download
LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034
M.Sc. DEGREE EXAMINATION – CHEMISTRY

FOURTH SEMESTER – April 2009
CH 4808 / 4805 / 4803 – ELECTROCHEMISTRY
Date & Time: 21/04/2009 / 9:00 – 12:00 Dept. No. Max. : 100 Marks
Part–A (20 Marks)
Answer ALL questions (10 x 2 = 20)
 Calculate the ionic strength of a solution obtained by mixing 50 ml of 0.02 M
Na_{2}SO_{4} and 50 ml of 0.02 M cerium (III) sulphate solutions.  Mention the factors affecting the thickness of the ionic atmosphere of an electrolytic solution.
 E^{°}_{red} of Au^{+}/Au is 1.68 V, E^{°}_{red} Au^{3+}/Au is 1.50 V. Calculate E^{°}_{oxi} of Au^{+}/Au^{3+}
at 25°  Calculate the zeta potential of a colloidal particle in aqueous solution that has an
electrophoretic mobility of 1.1 10^{8} m^{2} 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.  What is ‘Dorn Effect’?
 Draw the general pattern of the plot of current density vs overvoltage for an electrode having symmetry factor 0.75.
 What do you mean by the high field approximation of the ButlerVolmer equation.
 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.
 Bring out the difference between voltammetry and polarography.
 Differentiate between half wave and standard reduction potentials.
PartB (40 Marks)
Answer ANY EIGHT questions (8 x 5 = 40)
 Deduce Lippmann’s equation and mention its significance.
 Explain the influence of electrolytes on electrokinetic effects.
 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 KNO_{3 (aq)} solution?  Calculate K_{h} for NH_{4}Cl if the EMF of the cell.
Pt½H_{2}(1 atm)½NH_{4}Cl(0.2M) ½½ KCl(1M)½Hg_{2}Cl_{2}½Hg
at 25° C is 0.574 V and E°_{red} of calomel electrode is 0.28 V.
 Determine the potential due to ionic atmosphere around cation at 25° C for
10^{3}M CaCl_{2}(aq) if Î_{0} = 8.854 ´ 10^{12} C^{2}J^{1}m^{1} and dielectric constant of water is
3.  Explain Wien’s effect and its importance in the study of strong electrolytes.
 Electrolysis of a solution of Cu^{2+} produces 16 mg of Cu in 2 minutes. Calculate the rate of the reaction.
 What do you mean by non polarisable electrode? How is it related to its current density?
 Calculate the current density across an electrode (β = 0.45) at an applied potential of 0.23V if its equilibrium potential is 0.09V
 Explain migration and diffusion currents. Which current is significant in poloragraphy? How is it achieved?
 The dissolution of iron follows the following mechanism:
Fe + H_{2}O FeOH + H^{+ }+ e^{– } ; Eq Const K_{1}……….……1
FeOH FeOH^{+ } + e^{– ; }Eq Const K_{2}……….…….2
FeOH^{+} + H^{+ } Fe^{2+ }+ H_{2}O ; Eq Const K_{3 }…………….3
Determine its transfer coefficients if step2 is the rate determining step.
 Explain the electrochemical reduction of a typical aromatic ketone.
PartC (40 Marks)
Answer ANY FOUR questions (4 x 10 = 40)
 What is the need for a model on electrical double layer? Explain HelmohlltzPerrin model and mention its defects. (3 + 5 + 2)
 (a) Mention the assumptions of DebyeHuckel theory and explain any one
application of DebyeHuckel limiting law equation. (3 + 4)
(b) What is the need to modify the limiting law equation. (3)
 Explain any two of the following:
 Relaxation effect
 Electroosmosis
 GouyChap mann model of electrical double layer
 van’t Hoff factor.
 Derive the relation between current density and applied potential for an electrode undergoing multistep multi electron reaction
 Define limiting current. Derive an expression for it relating to concentration on the basis of the concept of concentration polarization.
 Explain the following with suitable examples and figures.
 Amperometric titrations
 Electrodes as anodic rectifiers
 Three electrode system.
Loyola College M.Sc. Chemistry April 2012 Electrochemistry Question Paper PDF Download
LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034
M.Sc. DEGREE EXAMINATION – CHEMISTRY
FOURTH SEMESTER – APRIL 2012
CH 4808 – ELECTROCHEMISTRY
Date : 16042012 Dept. No. Max. : 100 Marks
Time : 1:00 – 4:00
PART – A
Answer ALL questions (10 x 2 = 20 marks)
 Mention the factors that favour ion association in an electrolytic solution.
 Determine the mean activity coefficient of 10^{3} m La(NO_{3})_{3} in water using
Debye – Huckellimitting law at 25^{o}C.
 Calculate the work of charging Li^{+} in vacuum. The radius of Li^{+} is 59 pm
(Î_{0} = 1.112 x 10^{10} C^{2} J^{1} m^{1}).
 Mention the evidences for the existence of ionic atmosphere around an ion of an electrolyte.
 What is zeta potential?
 What is voltametry? How does it differ from potentiometry?
 The ButlerVolmer equation under certain condition(s) can be expressed in the form: i = A Sinh(kη). Express the values of A and k in terms of the corresponding physical constants?
 Explain the condition under which an electrode will (i) show ohmic behavior (ii) act as a rectifier.
 Define stoichiometric number. How can it be determined experimentally?
 Explain concentration polarization. What are the factors contributing to it?
PART – B
Answer any EIGHT questions (8 x 5 = 40 marks)
 For the cell, Zn + 2 AgCl_{(s)}® 2 Ag + Zn^{2+} + 2Cl^{–}.E^{o} cell at 298 K is 1.034 V. Evaluate DG^{o}, DH^{o} and DS^{o} for the cell if the temperature coefficient of EMF is 54 x 10^{4 }V/K.
 Calculate the thickness of the ionic atmosphere in 0.1 M KCl at 298 K in
nitro benzene (Î = 34.8). (Î_{o} = 8.85 x 10^{12} C^{2}J^{1} m^{1}).
 Differentiate chemical potential and electrochemical potential and deduce the relevant equations.
 Discuss the salient features of Helmholtz – Perrin model of electrical double layer.
 How is Debye Huckel – Onsagar equation verified experimentally?
 Calculate the molar conductivity of NaI in acetone. The viscosity of acetone is 3.16 milli poise. The radii of Na^{+}and I^{–} ions are 260 and 300 pm respectively. (1 poise = 10^{7} ohm C^{2} om^{3}).
 The cathodic symmetry factor, β of an electrode is less than 0.5. Draw the following curves in a plot of current density vs applied potential:
(i) Anodic current density, i_{a} (ii) Cathodic current density, i_{c}
(iii) Net current density, i
 The current density of an electrode for an over potential 10 mV was found to be 0.62mAcm^{2}. What will be the current density when the over potential applied is 100 mV, if its cathodic symmetry factor is 0.56.
 Calculate the minimum potential required for the discharge of Cu^{2+} from its 5×10^{3}M solution at 298K (SRP of Cu^{2+}/ Cu = 0.34V).
 The reduction of Fe^{2+} to Fe follows the following mechanism:
Fe^{2+ }+ H_{2}O FeOH^{+} + H^{+ }eqconts K_{1}…….(1) Fast
FeOH^{+}+ e FeOH eq conts K_{2}……. (2) Fast
FeOH + H^{+ }+ e Fe +H_{2}O eq conts K_{3}…….(3) Slow
Write the expression for the current density of the rate determining step and step2.
 Derive the relation between applied potential and current density for a cathodic reaction on a mercury surface.
 Define residual, diffusion and limiting currents. How do they arise and how are they related to each other?
PART – C
Answer any FOUR questions (4 x 10 = 40 marks)
 a) Mention the assumptions of Debye – Huckel theory of activity coefficients.
 b) Derive linearised Poisson – Boltzmann equation and mention its
significance.
 Explain any two of the following
 a) Electrocapillarity b) Grotthus type conduction
 c) Electrokinetic phenomena d) Diverse ion effect.
 a) Discuss the theoretical basis for Debye – Huckel – Onsager equation.
 b) How is solvation number determined?
 (a) Derive the relation between current and over potential for a simple
one electron electrode system.
(b) Deduce Nernst equation from the above relation.
 (a) What do you mean by electrode rectification?
(b) Discuss ButlerVolmer equation for different symmetry factors,
β (<0.5 , 0 &>0.5)
 The evolution of hydrogen on a metal surface follows a twostep mechanism, viz., a fast equilibrium discharge of H_{3}O^{+} followed by the slow chemical desorption of the adsorbed H atoms. Write the mechanism of the reaction and hence determine the order and the transfer coefficient for the discharge process.