CBSE Guess > Papers > Important Questions > Class XII > 2007 > Chemistry > Electrochemistry
Electrochemistry
Q. 1. Resistance of a conductivity cell filled with0.1M KCl is 100ohm.If the resistance of the same cell filled with 0.02M kCl is520ohm,calculate the conductivity and molar conductivity of 0.02M KCl solution.Conductivity of 0.1M KCl is 1.29S/m
Q. 2. Resistance of a column of 0.05M NaOH solution of diameter1cm and length 50cm is 5.55 x 103ohm. Calculate its resistivity and conductivity.Calculate its molar conductivity in S m2mol-1
Q. 3. Resistance of 0.01M CH3COOH solution is 2220 ohm.Cell constant(G*)=0.366cm-1. Calculate the degree of dissociation of CH3COOH at this concentration. Given Λ0 HCl, NaCl and CH3COONa are 425,128 and 96 Scm2mol-1 respectively .Also find dissociation constant Ka.
Q. 4. Λo Al2(SO4)3 is 858 S cm2 mol-1. Determine Λ0 Al3+ if Λ0 of SO42-is 160 S cm2 mol-1.
Q. 5. Calculate the amount of chlorine gas by passing a current of 1.5amperes for 90 minutes through molten NaCl.
Q. 6. How many coulomb of electricity is needed for the following reactions ; (a)2moles of MnO4 - to Mn2+ (b)1mole of of H2O to O2 (c) 9grams of Al from molten AlCl3.
Q. 7. Silver is electrodeposited by passing a current of 0.2amperes for 3hours on a vessel of surface area 800cm2. Calculate the thickness of silver deposited.Density of Ag is 10.8g/cm3.
Q. 8. Three electrolytes A,B,C containing solution of ZnSO4 ,AgNO3 and CuSO4 respectively are connected in series. 1.45g of silver deposited by passing 1.5 amperes. How long did the current flow? Calculate the amount of silver and copper deposited.Atomic masses Ag = 108 Cu = 63.5 Zn = 65.5
Q. 9. Calculate the e.m.f of the cell. Cr/Cr3+║Fe2+/Fe Given E0 Cr3+/Cr =−0.74V E0 Fe2+/Fe =−0.44V (0.01M) ( 0.01M)
Q. 10. Calculate the cell potential at 298K. Sn4++Zn(s)→Sn2++Zn2+ E0 Sn2+/ Sn2+ = 0.13v E0 Zn2+ /Zn = −0.76V (1.5M) (0.5M} (2M)
Q. 11. Calculate the equilibrium constant and the work done by the cell.
Ni(s)+Cu2+→Cu(s) + Ni2+ E0Ni2+/Ni = - 0.25V E0Cu2+/Cu = + 0.34V
Q. 12. Find the potential of the electrode Mg2+/Mg
Mg2++2e− → Mg E0 Mg2+/Mg =−2.36V (Mg2+)=0.1M
Q. 13. Find the e.m.f of the cell Pb/Pb2+ (0.001M)║Pt,Cl2(1.5atm)/ Cl--(1M) E0 Cl2/Cl- = 1.36V E0Pb2+/Pb = −0.13V
Q. 14. Electrolysis of a metal salt solution resulted in deposition of 1g of the metal by passing a current of 1.5amperes for 2hours.Determine the charge carried by the metal if it has an atomic mass of 27g/mole.
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