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ELECTRO CHEMISTRY

ELECTRO CHEMISTRY  
     Each question is of three marks.                                      .
1.(a)Define Faraday constant.How is it derived?                                                                                           
    (b)The resistance of a conductivity cell containing 0.001 M KCl solution at 298 K is 1500Ω.
          What is the cell constant if conductivity of 0.001 M KCl  solution at 298 K is 0.146 X 10-3 S/cm.
 2.The standard electrode potential for Daniel cell is 1.1 V .Calculate the standard Gibb’s energy for
     The reaction  Zn(s) +Cu2+(aq)  -------------  Zn2+(aq) +Cu(s)
 3.Describe the preparation and electrode reactions of  fuell cell .                                                                
 4.Explain Kohlrausch’s law of independent migration of ions.Write its one application.
 5.How conductivity of an unknown solution be determined ?explain 
 6. If a current of 0.5 amp flows through a metallic wire for 3 hrs, then how many electrons would flow throughthewire?
 8. Predict the products of electrolysis of
. An aqueous solution of AgNO with platinum electrodes
. A dilute solution of H2SO4 with platinum electrodes
. An aqueous solution of CuCl2 with platinum electrode. 
 9.Explain the chemistry of lead storage battery  while recharging .                                                                                                                           
10.Write the Nernst equation  and calculate the emf of the following cell at 298 K:
    Cu(s)I Cu2+(0.130M) II Ag+(1.00x10-4M) IAg(s)
    Given E0   Cu2+ /Cu =+0.34 V and E0   Ag+ /Ag =+0.80 V.                                                                   
11 . What are secondary cells? Give the anode and cathode reaction of nickel-cadmium  cell.  
12. Conductivity of 0.00241 M acetic acid is 7.896 x 10-5S/cm .If Λ0 for acetic acid is 390.5 Scm2/mol,what is the degree of dissociation ?   
13.What does the negative  value of E0 indicate?
      Why is the equilibrium constant K, related to E0 cell and not  Ecell ?
14.Rusting of iron is quicker in saline water than in ordinary water.why?
15.What would happen if the protective tin coating over an iron bucket is broken in some places?
      Can a nickel spatula be used to stir a solution of copper sulphate  ?Justify
16.Which out of 0.1 M HCl and 0.1 M NaCl ,do you expect have greater Λ∞ and why?
17.Which will have greater molar conductivity? Solution containing 1 mol KCl in 200 cc or 1 mol of KCl in 500 cc.  
18.How will the value of Ecell change in an electrochemical cell involving the following reaction of the concentration of Ag+ (aq) is increased?
What will be e.m.f. when the cell reaches equilibrium:
Mg +2 Ag+  ------- Mg 2+ +Ag
19.In a cell reaction the equilibrium constant K is less than one. Is E0 for the cell positive?
What will be the value of K for E0= 0?
20.Write the units of resistance ,conductivity and resistivity .How are these related with eachother?


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