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Electro Chemistry 3 Mark Book Back Question Paper With Answer Key

12th Standard

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Chemistry

Time : 01:30:00 Hrs
Total Marks : 63

     3 Marks

    21 x 3 = 63
  1. State Faraday’s Laws of electrolysis

  2. Describe the construction of Daniel cell. Write the cell reaction.

  3. Why is anode in galvanic cell considered to be negative and cathode positive electrode?

  4. The conductivity of a 0.01M solution of a 1 :1 weak electrolyte at 298K is 1.5\(\times\)10-4 S cm−1.
    i) molar conductivity of the solution
    ii) degree of dissociation and the dissociation constant of the weak electrolyte
    Given that
    \(\lambda^{0}_{cation}=248.2 \ S\) cm2 mol-1
    \(\lambda^{0}_{anlon}=51.8 \ S\) cm2 mol-1

  5. Which of 0.1M HCl and 0.1 M KCl do you expect to have greater \(\stackrel{0}{\Lambda}_{\mathrm{m}}\)and why?

  6. Arrange the following solutions in the decreasing order of specific conductance.
    i) 0.01M KCl
    ii) 0.005M KCl
    iii) 0.1M KCl
    iv) 0.25M KCl
    v) 0.5M KCl

  7. Why is AC current used instead of DC in measuring the electrolytic conductance?

  8. 0.1M NaCl solution is placed in two different cells having cell constant 0.5 and 0.25 cm-1 respectively. Which of the two will have greater value of specific conductance.

  9. A current of 1.608A is passed through 250 mL of 0.5M solution of copper sulphate for 50 minutes. Calculate the strength of Cu2+ after electrolysis assuming volume to be constant and the current efficiency is 100%.

  10. Can Fe3+ oxidises Bromide to bromine under standard conditions?
    Given: \({ E }_{ { Fe }^{ 3+ }|{ Fe }^{ 2+ } }^{ 0 }=0.771V\)\(\\ { E }^{0}_{ { Br }_{ 2 }|{ Br }^{ - } }=1.09V\).

  11. Is it possible to store copper sulphate in an iron vessel for a long time?
    Given : \(E^{0}_{Cu^{2+}|Cu} = 0.34\) V and \(E^{0}_{Fe^{2+}|Fe} = -0.44\)V.

  12. Two metals M1 and M2 have reduction potential values of -xV and +yV respectively. Which will liberate H2 and H2SO4.

  13. Reduction potential of two metals M1 and M2 are \(E^{0}_{M^{2+}_{1}|M_{1}} = -2.3V\) and \(E^{0}_{M^{2+}_{1}|M_{1}} = 0.2V\) Predict which one is better for coating the surface of iron. Given : \(\mathrm{E}_{\mathrm{Fe}^{2+} \mid \mathrm{Fe}}^{\circ}=-0.44 \mathrm{~V}\)

  14. Calculate the standard emf of the cell: Cd|Cd2+||Cu2+|Cu and determine the cell reaction. The standard reduction potentials of Cu2+|Cu and Cd2+|Cd are 0.34V and -0.40 volts respectively. Predict the feasibility of the cell reaction.

  15. In fuel cell Hand O2 react to produce electricity. In the process, H2 gas is oxidised at the anode and O2 at cathode. If 44.8 litre of H2 at 250C and 1 atm pressure reacts in 10 minutes, what is average current produced? If the entire current is used for electro deposition of Cu from Cu2+, how many grams of Cu deposited?

  16. The same amount of electricity was passed through two separate electrolytic cells containing solutions of nickel nitrate and chromium nitrate respectively. If 2.935 g of Ni was deposited in the first cell. The amount of Cr deposited in the another cell? Give : molar mass of Nickel and chromium are 58.74 and 52gm-1 respectively.

  17. A copper electrode is dipped in 0.1M copper sulphate solution at 25oC. Calculate the electrode potential of copper. [Given: E0Cu2+|Cu = 0.34V].

  18. For the cell Mg (s) Mg2+(aq)||Ag+(aq)|Ag(s), calculate the equilibrium constant at 250C and maximum work that can be obtained during operation of cell. Given: \(E^{0}_{Mg^{2+}|Mg}\)=-237V and \(E^{0}_{Ag^{2+}|Ag}\) = 0.80V.

  19. 9.2\(\times\)1012 litres of water is available in a lake. A power reactor using the electrolysis of water in the lake, produces electricity at the rate of 2\(\times\)106 Cs−1 at an appropriate voltage. How many years would it take to completely electrolyse the water in the lake. Assume that there is no loss of water except due to electrolysis.

  20. Write a note on sacrificial protection.

  21. Ionic conductance at infinite dilution of Al3+ and SO4 2- are 189 and 160 mho cm2 equiv-1. Calculate the equivalent and molar conductance of the electrolyte Al2(SO4)3 at infinite dilution.

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