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Ans: (c)

Electro chemistry Multiple choice Questions:- 1) In an electro chemistry cell the electrical energy is obtained at the cost of a) Mechanical energy b) internal energy c) chemical energy d) Thermal energy. Ans: (c). c) chemical energy.

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Ans: (c)

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  1. Electro chemistryMultiple choice Questions:-1) In an electro chemistry cell the electrical energy is obtained at the cost of a) Mechanical energy b) internal energy c) chemical energy d) Thermal energy Ans: (c) c) chemical energy

  2. 2) The device used to bring about non-spontaneous red px reactions by supplying electrical energy is called a) electrochemical cell b) electrolytic cell c) dry cell d) De Ans: (b) b) electrolytic cell

  3. 3) Some statements are given below a) The electrolytic conduction is due to the migration of ions through the electrolyte b) The postage of electric current through the electrolyte leads to the chemical changes c) Electrolysis is a spontaneous redox reaction. d) Sodium chroride carries electricity only in its aquarous solution. (Among the above the correct statements are) Ans : (c) c) Electrolysis is a spontaneous redox reaction.

  4. 4) One & araday of electricity liberates the amount of ions which is equal to its a) molecular weight b) atomic weight c) equivalent weight d) none of these Ans: (a) a) molecular weight

  5. 5) The atomic weight of Cu is 64. The weight Cu liberated from CuSo4 solution by passing a current of 0.965 ampere for 1000 seconds would be a) 0.64 g b) 0.64 kg c) 0.32 kg d) 0.32 x 103 kg Ans : (a) a) 0.64 g

  6. 6) Some statement are given below a) The weight of on ion liberated during electrolysis is directly proportional to the quantity of current passed. b) Coulomb is the product of current in ampere and time. c) the weight of substance formed at the electrode by the same amount of electricity is proportional to the equivalent weight of that substance d) The minimum weight of that substance which can be obtained during electrolysis is its electrochemical equivalent (Among the above the false statement are a, b & d) Ans: (c) c) the weight of substance formed at the electrode by the same amount of electricity is proportional to the equivalent weight of that substance

  7. 7) The atomic weight of Al is ‘X’ the electrochemical equivalent of Al in the solution of Aluminium sulphate will be a)3X/F b) X/3F c) 2X/F d) X/F Ans : (b) b) X/3F

  8. 8) The current of 5000 MA is passed through a solution for 10 seconds. The no. of coulombs passed are a) 50000 b) 500 c) 5000 d) 50 Ans : (d) d) 50

  9. 9) The No. of coulombs required to liberate 0.224 dm3 of chlorine at 00C @ 1 atm (NTP) pressure is a) 2 X 965 b) 965/2 c) 965 d) 9650 Ans: (a) a) 2 X 965

  10. 10) The No. of coulombs required to liberate 1.12 dm3 of H2 at 2730C and 2 atm pressure is a) 2 X 9650 b) 9650 c) 4 X 9650 d) 965 Ans: (c) c) 4 X 9650

  11. 11) The volume of O2 at STP by the passage of 2 for a day of electric charge through acidulated water is a) 22.4 Lit. b) 5.6 Lit. c) 11.2 Lit. d) 2.24 Lit. Ans: (c) c) 11.2 Lit.

  12. 12) The volume of H2 liberated at 2730C and at atm pressure by the passage of 1 Euroaday of electricity through HCL solution is a) 11.2 dm3 b) 22.4 dm3 c) 44.8 dm3 d) 5.6 dm3 Ans: (b) b) 22.4 dm3

  13. 13) 2 X 10-3 kg of on element i.e. deposited by passing 2A current for 16 min and 5 second through a solution. The equivalent weight of the element is a) 100 b) 50 c) 25 d) 200 Ans: (a) a) 100

  14. 14) The chemical equivalent of the element A,B and C are 4,12 and 20 respectively. The weight of A, B and C liberated by 1000 coulomb will be in the rating of a) 5 : 3 : 1 b) 1 : 3 : 5 c) 1 : 1 : 1 d) 1 : 2 : 2 Ans : (b) b) 1 : 3 : 5

  15. 15) The electro chemical equivalent of metal A and B are in the ratio of X:Y. If a given quantity of electricited deposit & weight of A, the weight of B deposited by the same quantity of electricity would be a) WY/X b) WY/Wxg c) Wg. D) WX/Yxg Ans: (a) a) WY/X

  16. 16) The atomic weight of elements x and y are in the ratio of 1:2 coulombs deposit equal weights of these two elements. Then ik valency of x is 2 that of y is a) 2 b) 1 c) 4 d) 3 Ans : (c) c) 4

  17. 17) If the current of x ampere is passing through a solution for t min. The number faradays passing area) 60 xtb) xtc) 60xt / 96500d) xt / 96500 Ans : (c) c) 60xt / 96500

  18. 18) One horse power is equal to a) 1000 J b) 647 watt c) 746 Watt d) 1000 KJ Ans: (c) c) 746 Watt

  19. 19) Some statement are given below A) Joule is the unit of work B) Faraday is the unit of electric current C) Watt is the work performed at the rate of 1 Joule per second D) Volt = Ohm x AmpereAmong the above the true statements are a) only A & C b) only A,B & D c) only A,C & D d) all Ans : (c) c) only A,C & D

  20. 20) The cell reaction of the Daniall cell in the standard state can be correctly represented as a) Zn (s) + Cu2- (aq)  Zn2+ (aq) + Cu (s)  b) Zn (s) + Cu2- (aq) (1M)  Zn2+ (aq)(1M) + Cu (s) c) Zn (s) + Cu2- Zn2+ + Cu (s)  d) Zn2- (aq)(1M) + Cu (s)  Zn (s) + Cu2+ (aq)(1M)  Ans : (b) b) Zn (s) + Cu2- (aq) (1M)  Zn2+ (aq)(1M) + Cu (s)

  21. 21) During the working of the Daniell cell, which of the following happens a) The size of the Zn rod remains same but the blue colour of CuSo1 solution becomes faint b) The size of the Zn rod is reduced and the blue colour of CuSo4 solution becomes faint. c) The size of the Zn rod reduced but there is no change in the intensity of colour of the CuSo4 solution. d) The size of the Zn rod as well as the intensity of the colour of CuSo4 solution remain unchanged. Ans: (b) b) The size of the Zn rod is reduced and the blue colour of CuSo4 solution becomes faint.

  22. 22) Some Statements are given belowA) In an electrochemical cell oxidation takes place at anode.B) In an electrochemical cell reduction takes place at cathode.C) In takes Daniell cell the Cu electrode grows in size during the working of the cell.D) The salt bridge maintains electrical neutrality of the half -cell ionic solutions.Among the above the wrong statement is a) Only B b) Only C c) Only A d) None Ans : (d) d) None

  23. 23) 25. In the cell; Pt, O2 (g)| OH- || Cl- | Cl2 (g) Pt, the anode half cell reaction is a) OH  ½ O2 + ½ H2 + e b) 2OH  O2 + H2 + 2e c) 2OH  ½ O2 + H2O + 2e d) ½ O2 + H2O + 2e 2OH Ans : (c) c) 2OH  ½ O2 + H2O + 2e

  24. 24) In a saturated calomel electrode the KCl solution is saturated with a) Only KCl b) Only calomel c) Both KCl and calomel d) None Ans : (c) c) Both KCl and calomel

  25. 25) The potential of a calomel electrode depends on a) concentration of KCl only b) temperature only c) both, the concentration of KCl and temperature d) its construction. Ans : (c) c) both, the concentration of KCl and temperature

  26. 26) The standard reduction potential of the metal A, B and C are in decreasing order. Which of these will always behave as the anode when coupled with the other two separately to form a cell ? a) A b) B c) C d) can not be predicted Ans : (c) c) C

  27. 27) The S.O.P values of metals A, B and x and y respectively. If x > y, the standard EMF of the cell containing these electrodes would be a) x – y b) y – x c) x + y d) unpredictable Ans: (a) a) x – y

  28. 28) The metals X, Y and Z follow one another in the same order in the E.M.F. series of S.O.P. On this basis some statements are made belowA) The ease of oxidation is in the order X > Y > ZB) The reducing power decreases in the order X > Y > ZC) X will displace Y and Z from their solutions.D) The maximum E.M.F. if the cell will be obtained by using X and Y as electrodes.Among the above the correct statements are a) Only A, B & D b) Only A, C & D c) Only A, B & C d) All Ans : (c) c) Only A, B & C

  29. 29) When electricity is passed through a solution of AlCl3, 13.5 g of Al (At. Wt. 27) is deposited. The number of Faradays passed through the solution must be a) 0.5 b) 1 c) 1.5 d) 2 Ans: (c) c) 1.5

  30. 30) Faraday’s laws of electrolysis are concerned with a) equivalent weight b) atomic weight c) molecular weight d) atomic number Ans : (a) a) equivalent weight

  31. 31) Which of the following will decompose by passing current through its aqueous solution ? a) glucose b) ethanol c) urea d) silver nitrate Ans : (d) d) silver nitrate

  32. 32) In electrolysis, oxidation takes place at a) anode b) cathode c) both, at the anode and at the cathode d) the surface of the solution Ans : (a) a) anode

  33. 33) 41. No. of faradays required to generate one gm atom of Mg from MgSO4 solution is a) 1 b) 2 c) 3 d) 4 Ans : (b) b) 2

  34. 34) During electrolysis of NaCl, the reaction Na+ +e- Na takes place at a) anode and called electronation. b) anode and called reduction. c) cathode and called oxidation. d) cathode and called electronation. Ans: (d) d) cathode and called electronation.

  35. 35) The atomic weight of Al is 27. The weight of aluminium deposited by a passage of 5 Faradays through aqueous Al2 (SO4)3 solution will be a) 27 g. b) 9 g. c) 45 g. d) 36 g. Ans : (c) c) 45 g.

  36. 36) During the electrolysis of the aqueous solution of NaCl the reaction taking place at anode is a) oxidation of sodium ions. b) oxidation of chloride ions. c) reduction of chloride ions. d) reduction of sodium ions. Ans: (b) b) oxidation of chloride ions.

  37. 37) Weight of copper deposited by the passage of 2 Faradays of electricity through the aqueous solution of cupric ions is equal to its a) atomic weight b) molecular weight c) electrochemical equivalent weight d) equivalent weight Ans: (a) a) atomic weight

  38. 38) The number of electrons involved in the reaction by passing one Faradays an electrolyte is a) 96500 b) 12 X 1023 c) 6 X 1023 d) 96500 X 6 X 1023 Ans: (c) c) 6 X 1023

  39. 39) The number of coulombs equal to one Faraday is a) 95600 b) 96500 c) 95500 d) 93600 b) 96500 Ans: (b)

  40. 40) During the electrolysis of NaCl solution the gas liberated at cathode is a) Cl2 b) H2 c) O2 d) H2 and O2 b) H2 Ans: (b)

  41. The amount of an ion discharged during electrolysis in not directly proportional to a) Time b) strength of current c) equivalent weight d) concentration of solution d) concentration of solution Ans: (d)

  42. 42) Faraday’s laws of electrolysis will fail if a) temperature is changed b) inert electrodes are used c) concentration of the solution is changed d) none of these d) none of these Ans: (d)

  43. 43) The unit of electrochemical equivalent is a) gram/sec b) gram/ampere c) gram/coulomb d) gram/Faraday c) gram/coulomb Ans: (c)

  44. The atomic weight of Al is 27. The ECE of Al in AlCl3 solution is a) b) c) d) Ans: (d)

  45. 45) The charge needed to liberate 0.5 gm atomic weight of a divalent element is a) 96500 C b) 48250 C c) 2 Faraday d) 5 Faraday a) 96500 C Ans: (a)

  46. 46) The molten electrolyte conducts electricity due to the presence of a) free electrons b) free ions c) free molecules d) free atoms b) free ions Ans: (c)

  47. 47) A solution of electrolyte in water, when electrolysed, liberated H2 at the cathode and Cl2 at the anode. The electrolyte must be a) H2SO4 b) CuCl2 c) NaCl d) Na2SO4 c) NaCl Ans: (c)

  48. 48) In electrolysis of a fused salt, the weight of a substance liberated at the electrode is independent of a) temperature b) current intensity c) electrochemical equivalent of ion d) time for electrolysis a) temperature Ans: (a)

  49. 49) A certain current liberates 0.504 x 10-3 kg of H2 in a certain time. The weight of copper (at wt. 63.6) liberated by the same current in the same time from CuSO4 Solution is a) 15.9 kg b) 63.6 kg c) 31.8 x 10-3 d) 15.9 x 10-3 kg d) 15.9 x 10-3 kg Ans: (d)

  50. 50) Current is passed through the solutions of silver nitrate and copper sulphate connected in series. The weight of Ag (At wt. 108) deposited in 10.8 g. The weight of Cu (At wt. 64) deposited will be a) 6.4 g b) 3.2 g c) 1.6 g d) 10.8 g b) 3.2 g Ans: (b)

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