{"id":12769,"date":"2025-09-22T14:38:35","date_gmt":"2025-09-22T13:38:35","guid":{"rendered":"https:\/\/mcqsadda.com\/?p=12769"},"modified":"2025-10-22T10:22:47","modified_gmt":"2025-10-22T09:22:47","slug":"electrolysis-top-100-mcqs-with-answer-and-explanation","status":"publish","type":"post","link":"https:\/\/mcqsadda.com\/index.php\/2025\/09\/22\/electrolysis-top-100-mcqs-with-answer-and-explanation\/","title":{"rendered":"Electrolysis Top 100 MCQs With Answer and Explanation"},"content":{"rendered":"\n

1. Electrolysis is:<\/mark><\/strong>
A) Chemical reaction without electricity
B) Chemical decomposition using electricity
C) Reaction in batteries
D) None of these
Answer:<\/strong> B
Explanation:<\/strong> Electrolysis uses electric current to decompose ionic compounds.<\/p>\n\n\n\n

2. Electrolyte is:<\/mark><\/strong>
A) Substance that does not conduct electricity
B) Substance that conducts electricity in molten or aqueous state
C) Substance that is a metal
D) Non-conductor
Answer:<\/strong> B
Explanation:<\/strong> Electrolytes dissociate into ions \u2192 conduct current.<\/p>\n\n\n\n

3. Anode is:<\/mark><\/strong>
A) Positive electrode
B) Negative electrode
C) Neutral
D) None
Answer:<\/strong> A
Explanation:<\/strong> Oxidation occurs at anode \u2192 attracts anions.<\/p>\n\n\n\n

4. Cathode is:<\/mark><\/strong>
A) Positive electrode
B) Negative electrode
C) Neutral
D) None
Answer:<\/strong> B
Explanation:<\/strong> Reduction occurs at cathode \u2192 attracts cations.<\/p>\n\n\n\n

5. Oxidation occurs at:<\/mark><\/strong>
A) Anode
B) Cathode
C) Both electrodes
D) None
Answer:<\/strong> A
Explanation:<\/strong> Anode is site of electron loss.<\/p>\n\n\n\n

6. Reduction occurs at:<\/mark><\/strong>
A) Anode
B) Cathode
C) Both
D) None
Answer:<\/strong> B
Explanation:<\/strong> Cathode is site of electron gain.<\/p>\n\n\n\n


7. Example of molten electrolyte electrolysis:<\/mark><\/strong>
A) Molten NaCl
B) NaCl solution
C) Water
D) HCl gas
Answer:<\/strong> A
Explanation:<\/strong> Molten NaCl decomposes \u2192 Na\u207a reduced, Cl\u207b oxidized.<\/p>\n\n\n\n

8. Electrolysis of aqueous NaCl produces:<\/mark><\/strong>
A) H\u2082 + Cl\u2082 + NaOH
B) Na + Cl\u2082
C) NaOH + H\u2082O
D) NaHCO\u2083
Answer:<\/strong> A
Explanation:<\/strong> Water is reduced to H\u2082 at cathode; Cl\u207b oxidized to Cl\u2082 at anode.<\/p>\n\n\n\n

9. Electrolysis of CuSO\u2084 using copper electrodes deposits:<\/mark><\/strong>
A) Cu at cathode; anode dissolves
B) Cu at anode; cathode dissolves
C) No change
D) CuSO\u2084 decomposes
Answer:<\/strong> A
Explanation:<\/strong> Copper anode oxidized \u2192 Cu\u00b2\u207a \u2192 reduced at cathode \u2192 Cu deposited.<\/p>\n\n\n\n

10. Electrolysis of molten lead bromide produces:<\/mark><\/strong>
A) Pb + Br\u2082
B) PbO + Br\u2082
C) Pb + Br\u207b
D) None
Answer:<\/strong> A
Explanation:<\/strong> Pb\u00b2\u207a reduced at cathode \u2192 Pb; Br\u207b oxidized at anode \u2192 Br\u2082.<\/p>\n\n\n\n

11. Faraday\u2019s first law states:<\/mark><\/strong>
A) Mass of substance \u221d time
B) Mass \u221d quantity of electricity
C) Mass \u221d voltage
D) Mass \u221d current\u00b2
Answer:<\/strong> B
Explanation:<\/strong> Mass deposited or liberated at electrode is proportional to charge passed.<\/p>\n\n\n\n

12. Faraday\u2019s second law states:<\/mark><\/strong>
A) Mass \u221d equivalent weight
B) Equal charge deposits equal moles
C) Mass \u221d voltage
D) Mass \u221d current
Answer:<\/strong> A
Explanation:<\/strong> Masses of different substances liberated by same charge \u221d equivalent weights.<\/p>\n\n\n\n

13. Unit of charge in electrolysis:<\/mark><\/strong>
A) Coulomb (C)
B) Ampere (A)
C) Volt (V)
D) Ohm (\u03a9)
Answer:<\/strong> A
Explanation:<\/strong> Q = I \u00d7 t; unit of charge is coulomb.<\/p>\n\n\n\n

14. 1 Faraday =<\/mark><\/strong>
A) 96485 C
B) 1 A
C) 1 V
D) 1 \u03a9
Answer:<\/strong> A
Explanation:<\/strong> 1 Faraday = charge of 1 mole of electrons.<\/p>\n\n\n\n

15. Electroplating is:<\/mark><\/strong>
A) Deposition of metal on object using electrolysis
B) Oxidation of metal
C) Chemical reaction
D) None
Answer:<\/strong> A
Explanation:<\/strong> Metal is coated for protection or decorative purpose.<\/p>\n\n\n\n

16. Example of electroplating:<\/mark><\/strong>
A) Silver plating on spoons
B) Galvanization of iron
C) Copper plating
D) All of these
Answer:<\/strong> D
Explanation:<\/strong> Electroplating applies metals for corrosion protection & aesthetics.<\/p>\n\n\n\n

17. Electrorefining is used to:<\/mark><\/strong>
A) Purify metals
B) Oxidize metals
C) Reduce metals
D) None
Answer:<\/strong> A
Explanation:<\/strong> Impure metal anode \u2192 pure metal deposited at cathode.<\/p>\n\n\n\n

18. Electrolysis of water produces:<\/mark><\/strong>
A) H\u2082 at cathode, O\u2082 at anode
B) H\u2082O \u2192 H\u2082O
C) O\u2082 at cathode, H\u2082 at anode
D) H\u2082 only
Answer:<\/strong> A
Explanation:<\/strong> 2H\u2082O \u2192 2H\u2082 + O\u2082; H\u2082 reduced, O\u2082 oxidized.<\/p>\n\n\n\n

19. Electrolyte in water electrolysis:<\/mark><\/strong>
A) Acidic or basic solution (H\u2082SO\u2084, NaOH)
B) Pure water
C) Metal
D) None
Answer:<\/strong> A
Explanation:<\/strong> Pure water conducts poorly \u2192 electrolyte added.<\/p>\n\n\n\n

20. Anode in water electrolysis is:<\/mark><\/strong>
A) Positive \u2192 O\u2082 evolved
B) Negative \u2192 H\u2082 evolved
C) Neutral
D) None
Answer:<\/strong> A
Explanation:<\/strong> Oxidation of OH\u207b \u2192 O\u2082 gas at positive electrode.<\/p>\n\n\n\n

21. Cathode in water electrolysis:<\/mark><\/strong>
A) Negative \u2192 H\u2082 evolved
B) Positive \u2192 O\u2082 evolved
C) Neutral
D) None
Answer:<\/strong> A
Explanation:<\/strong> Reduction of H\u207a ions \u2192 H\u2082 gas at negative electrode.<\/p>\n\n\n\n

22. Electrolysis of molten KCl produces:<\/mark><\/strong>
A) K + Cl\u2082
B) KClO\u2083
C) KOH
D) K\u2082O
Answer:<\/strong> A
Explanation:<\/strong> K\u207a reduced \u2192 K; Cl\u207b oxidized \u2192 Cl\u2082.<\/p>\n\n\n\n

23. Electrolysis of molten Al\u2082O\u2083 uses:<\/mark><\/strong>
A) Cryolite to lower melting point
B) NaCl
C) H\u2082SO\u2084
D) KClO\u2083
Answer:<\/strong> A
Explanation:<\/strong> Al\u2082O\u2083 melts at 2072\u00b0C; cryolite reduces temperature.<\/p>\n\n\n\n

24. Electrolysis of CuSO\u2084 using inert electrodes produces:<\/mark><\/strong>
A) Cu deposited at cathode; O\u2082 at anode
B) Cu at anode; O\u2082 at cathode
C) CuSO\u2084 unchanged
D) H\u2082 and O\u2082
Answer:<\/strong> A
Explanation:<\/strong> Cu\u00b2\u207a reduced \u2192 Cu; H\u2082O oxidized \u2192 O\u2082.<\/p>\n\n\n\n


25. Electrolysis depends on:<\/mark><\/strong>
A) Nature of electrolyte
B) Current passed
C) Electrode material
D) All of these
Answer:<\/strong> D
Explanation:<\/strong> Electrolysis efficiency and products depend on all three factors.<\/p>\n\n\n\n

26. Electrolysis of molten NaCl produces:<\/mark><\/strong>
A) Na at cathode, Cl\u2082 at anode
B) NaCl unchanged
C) NaOH + H\u2082
D) Na\u2082O + Cl\u2082
Answer:<\/strong> A
Explanation:<\/strong> Na\u207a reduced at cathode \u2192 Na; Cl\u207b oxidized at anode \u2192 Cl\u2082.<\/p>\n\n\n\n

27. Electrolysis of aqueous NaCl produces:<\/mark><\/strong>
A) NaOH + H\u2082 + Cl\u2082
B) Na + Cl\u2082
C) NaOH + H\u2082O
D) HCl only
Answer:<\/strong> A
Explanation:<\/strong> H\u2082O reduced \u2192 H\u2082; Cl\u207b oxidized \u2192 Cl\u2082; solution becomes NaOH.<\/p>\n\n\n\n

28. In electrolysis of CuSO\u2084 using Cu electrodes, anode dissolves because:<\/mark><\/strong>
A) Cu oxidized \u2192 Cu\u00b2\u207a
B) Cu reduced
C) Cu unchanged
D) Cu reacts with water
Answer:<\/strong> A
Explanation:<\/strong> Cu anode oxidized \u2192 Cu\u00b2\u207a \u2192 replenishes electrolyte.<\/p>\n\n\n\n

29. Cathode reaction in CuSO\u2084 electrolysis with Cu electrodes:<\/mark><\/strong>
A) Cu\u00b2\u207a + 2e\u207b \u2192 Cu
B) Cu \u2192 Cu\u00b2\u207a + 2e\u207b
C) H\u2082O \u2192 O\u2082 + 4H\u207a + 4e\u207b
D) SO\u2084\u00b2\u207b \u2192 S + O\u2082
Answer:<\/strong> A
Explanation:<\/strong> Cu\u00b2\u207a reduced at cathode \u2192 pure Cu deposited.<\/p>\n\n\n\n

30. Industrial use of molten NaCl electrolysis:<\/mark><\/strong>
A) Manufacture of Na metal
B) Manufacture of Cl\u2082
C) Manufacture of NaOH (from aqueous electrolysis)
D) All of these
Answer:<\/strong> D
Explanation:<\/strong> Electrolysis provides Na, Cl\u2082, and NaOH (in aqueous solution).<\/p>\n\n\n\n

31. Molten lead bromide electrolysis produces:<\/mark><\/strong>
A) Pb + Br\u2082
B) PbO + Br\u2082
C) Pb\u00b2\u207a + Br\u207b
D) None
Answer:<\/strong> A
Explanation:<\/strong> Pb\u00b2\u207a reduced \u2192 Pb; Br\u207b oxidized \u2192 Br\u2082.<\/p>\n\n\n\n

32. In aqueous electrolysis of CuSO\u2084 with inert electrodes, oxygen evolves at:<\/mark><\/strong>
A) Anode
B) Cathode
C) Both
D) None
Answer:<\/strong> A
Explanation:<\/strong> H\u2082O oxidation \u2192 O\u2082 at positive electrode.<\/p>\n\n\n\n

33. Hydrogen evolves at cathode in aqueous electrolysis if:<\/mark><\/strong>
A) Metal less reactive than H
B) Metal more reactive than H
C) Any metal
D) Only inert metal
Answer:<\/strong> B
Explanation:<\/strong> Less reactive metals (Cu\u00b2\u207a, Ag\u207a) reduced preferentially; more reactive \u2192 H\u2082 released.<\/p>\n\n\n\n

34. In molten electrolysis, cations are reduced at:<\/mark><\/strong>
A) Cathode
B) Anode
C) Both
D) None
Answer:<\/strong> A
Explanation:<\/strong> Positive ions move to cathode \u2192 gain electrons \u2192 reduced.<\/p>\n\n\n\n

35. In molten electrolysis, anions are oxidized at:<\/mark><\/strong>
A) Anode
B) Cathode
C) Both
D) None
Answer:<\/strong> A
Explanation:<\/strong> Negative ions move to anode \u2192 lose electrons \u2192 oxidized.<\/p>\n\n\n\n

36. Cryolite (Na\u2083AlF\u2086) is added to Al\u2082O\u2083 electrolysis to:<\/mark><\/strong>
A) Lower melting point
B) Increase melting point
C) Act as electrolyte
D) None
Answer:<\/strong> A
Explanation:<\/strong> Reduces Al\u2082O\u2083 melting point \u2192 energy saving in aluminium extraction.<\/p>\n\n\n\n

37. Aluminium is deposited at:<\/mark><\/strong>
A) Cathode
B) Anode
C) Electrolyte
D) Both electrodes
Answer:<\/strong> A
Explanation:<\/strong> Al\u00b3\u207a ions reduced \u2192 Al metal at cathode.<\/p>\n\n\n\n

38. Oxygen evolves at anode during Al\u2082O\u2083 electrolysis because:<\/mark><\/strong>
A) O\u00b2\u207b oxidized \u2192 O\u2082
B) Al\u00b3\u207a oxidized
C) Electrolyte decomposes
D) None
Answer:<\/strong> A
Explanation:<\/strong> Oxidation of oxide ions \u2192 O\u2082 gas.<\/p>\n\n\n\n

39. Electroplating of silver uses:<\/mark><\/strong>
A) AgNO\u2083 solution and silver cathode
B) CuSO\u2084 solution and copper cathode
C) NaCl solution and inert electrodes
D) None
Answer:<\/strong> A
Explanation:<\/strong> Metal cation reduced at cathode \u2192 coating on object.<\/p>\n\n\n\n

40. Electroplating is done to:<\/mark><\/strong>
A) Prevent corrosion
B) Decorate
C) Improve conductivity
D) All of these
Answer:<\/strong> D
Explanation:<\/strong> Electroplating enhances durability, aesthetics, and conductivity.<\/p>\n\n\n\n

41. Electrorefining of copper involves:<\/mark><\/strong>
A) Impure copper anode, pure copper cathode
B) Pure copper anode, impure copper cathode
C) Impure copper in electrolyte
D) None
Answer:<\/strong> A
Explanation:<\/strong> Impure Cu oxidized \u2192 pure Cu deposited at cathode.<\/p>\n\n\n\n

42. Electrolysis of molten calcium chloride gives:<\/mark><\/strong>
A) Ca + Cl\u2082
B) CaO + Cl\u2082
C) Ca\u00b2\u207a + Cl\u207b
D) None
Answer:<\/strong> A
Explanation:<\/strong> Ca\u00b2\u207a reduced \u2192 Ca metal; Cl\u207b oxidized \u2192 Cl\u2082 gas.<\/p>\n\n\n\n

43. Electrolysis of brine (NaCl solution) produces:<\/mark><\/strong>
A) Cl\u2082, H\u2082, NaOH
B) Na + Cl\u2082
C) HCl + NaOH
D) None
Answer:<\/strong> A
Explanation:<\/strong> Industrial method for producing chlorine, hydrogen, and caustic soda.<\/p>\n\n\n\n

44. Electrolysis of aqueous Na\u2082SO\u2084 produces:<\/mark><\/strong>
A) H\u2082 at cathode, O\u2082 at anode
B) Na + SO\u2084\u00b2\u207b
C) NaOH + H\u2082
D) Na\u2082O + H\u2082
Answer:<\/strong> A
Explanation:<\/strong> Inert electrodes \u2192 water reduced\/oxidized \u2192 H\u2082 and O\u2082.<\/p>\n\n\n\n

45. Copper is purified by electrorefining because:<\/mark><\/strong>
A) High purity required for electrical wiring
B) Impurities remain in solution as anode mud
C) Both A & B
D) None
Answer:<\/strong> C
Explanation:<\/strong> Electrorefining ensures high-purity copper deposition.<\/p>\n\n\n\n

46. In electrolysis, electrolyte must:<\/mark><\/strong>
A) Contain mobile ions
B) Be solid only
C) Be inert
D) None
Answer:<\/strong> A
Explanation:<\/strong> Current carried by movement of ions \u2192 essential for electrolysis.<\/p>\n\n\n\n

47. Industrial production of NaOH uses:<\/mark><\/strong>
A) Electrolysis of brine
B) Electrolysis of molten NaCl
C) Reaction of Na\u2082CO\u2083 with Ca(OH)\u2082
D) None
Answer:<\/strong> A
Explanation:<\/strong> Chlor-alkali process \u2192 NaOH, Cl\u2082, H\u2082.<\/p>\n\n\n\n

48. Cathode reaction in brine electrolysis:<\/mark><\/strong>
A) 2H\u2082O + 2e\u207b \u2192 H\u2082 + 2OH\u207b
B) Cl\u207b \u2192 Cl\u2082 + e\u207b
C) Na\u207a \u2192 Na
D) None
Answer:<\/strong> A
Explanation:<\/strong> Hydrogen produced by water reduction at cathode.<\/p>\n\n\n\n

49. Anode reaction in brine electrolysis:<\/mark><\/strong>
A) 2Cl\u207b \u2192 Cl\u2082 + 2e\u207b
B) Na\u207a + e\u207b \u2192 Na
C) H\u2082O \u2192 H\u2082 + O\u2082
D) None
Answer:<\/strong> A
Explanation:<\/strong> Chloride ions oxidized \u2192 Cl\u2082 gas at anode.<\/p>\n\n\n\n

50. Main industrial application of electrolysis:<\/mark><\/strong>
A) Metal extraction
B) Electroplating
C) Production of chemicals (Cl\u2082, H\u2082, NaOH)
D) All of these
Answer:<\/strong> D
Explanation:<\/strong> Electrolysis is widely used in metallurgy, plating, and chemical industries.<\/p>\n\n\n\n

51. Faraday\u2019s first law of electrolysis states:<\/mark><\/strong>
A) Mass of substance liberated \u221d time
B) Mass of substance liberated \u221d charge passed
C) Mass of substance liberated \u221d voltage
D) Mass of substance liberated \u221d current\u00b2
Answer:<\/strong> B
Explanation:<\/strong> The mass deposited or liberated at an electrode is proportional to the quantity of electricity (Q) passed.<\/p>\n\n\n\n

52. Faraday\u2019s second law of electrolysis states:<\/mark><\/strong>
A) Masses of different substances liberated by same charge \u221d their equivalent weights
B) Masses of different substances \u221d voltage
C) Masses of different substances \u221d current\u00b2
D) Masses of different substances \u221d time
Answer:<\/strong> A
Explanation:<\/strong> For the same quantity of electricity, substances with higher equivalent weight deposit more mass.<\/p>\n\n\n\n

53. 1 Faraday of electricity is equal to:<\/mark><\/strong>
A) 96485 C
B) 1 C
C) 1 A
D) 1 V
Answer:<\/strong> A
Explanation:<\/strong> 1 Faraday = charge of 1 mole of electrons = 96485 C.<\/p>\n\n\n\n

54. Charge (Q) passed during electrolysis is given by:<\/mark><\/strong>
A) Q = I \u00d7 t
B) Q = V \u00d7 t
C) Q = I \/ t
D) Q = V \/ I
Answer:<\/strong> A
Explanation:<\/strong> Total charge = current \u00d7 time; Q in coulombs, I in amperes, t in seconds.<\/p>\n\n\n\n

55. Mass deposited (m) at electrode is given by:<\/mark><\/strong>
A) m = (Eq \u00d7 Q) \/ F
B) m = Q \/ (Eq \u00d7 F)
C) m = I \/ t
D) m = F \/ Q
Answer:<\/strong> A
Explanation:<\/strong> Using Faraday\u2019s laws, m = (M \u00d7 Q) \/ (n \u00d7 F) \u2192 Eq = M\/n \u2192 m = (Eq \u00d7 Q)\/F.<\/p>\n\n\n\n

56. Electrochemical equivalent (Z) is:<\/mark><\/strong>
A) Mass deposited per coulomb of charge
B) Mass deposited per ampere
C) Mass deposited per mole
D) Charge per mass
Answer:<\/strong> A
Explanation:<\/strong> Z = m\/Q, m = mass deposited, Q = charge passed.<\/p>\n\n\n\n

57. Electrochemical equivalent of copper:<\/mark><\/strong>
A) 0.000329 g\/C
B) 0.00329 g\/C
C) 0.0329 g\/C
D) 0.329 g\/C
Answer:<\/strong> A
Explanation:<\/strong> Z = M\/nF = 63.5\/(2 \u00d7 96485) \u2248 0.000329 g\/C.<\/p>\n\n\n\n

58. Mass of silver deposited by 1 A current in 1 s:<\/mark><\/strong>
A) 0.00118 g
B) 0.0118 g
C) 0.118 g
D) 1.18 g
Answer:<\/strong> A
Explanation:<\/strong> Z(Ag) = 0.001118 g\/C \u2192 m = I \u00d7 t \u00d7 Z = 1 \u00d7 1 \u00d7 0.001118 \u2248 0.00118 g.<\/p>\n\n\n\n

59. Mass of Cu deposited by 2 F of electricity:<\/mark><\/strong>
A) 63.5 g
B) 31.75 g
C) 127 g
D) 95.25 g
Answer:<\/strong> C
Explanation:<\/strong> 2 F = 2 \u00d7 96485 C \u2192 Cu\u00b2\u207a \u2192 1 mol Cu per F \u2192 2 F \u2192 2 \u00d7 63.5 = 127 g.<\/p>\n\n\n\n

60. Number of moles of electrons to deposit 1 mole of Al\u00b3\u207a:<\/mark><\/strong>
A) 3 moles
B) 1 mole
C) 2 moles
D) 4 moles
Answer:<\/strong> A
Explanation:<\/strong> Al\u00b3\u207a needs 3 electrons for reduction \u2192 3 moles of electrons per mole Al.<\/p>\n\n\n\n

61. Electrolysis of molten KCl requires:<\/mark><\/strong>
A) Cathode \u2192 K\u207a reduced, Anode \u2192 Cl\u207b oxidized
B) Cathode \u2192 Cl\u207b reduced, Anode \u2192 K\u207a oxidized
C) Cathode \u2192 K\u207a oxidized, Anode \u2192 Cl\u207b reduced
D) Cathode \u2192 Cl\u207b oxidized, Anode \u2192 K\u207a reduced
Answer:<\/strong> A
Explanation:<\/strong> Cations reduced at cathode, anions oxidized at anode.<\/p>\n\n\n\n

62. Electrolysis of CuSO\u2084 with inert electrodes produces:<\/mark><\/strong>
A) Cu at cathode, O\u2082 at anode
B) Cu at anode, O\u2082 at cathode
C) H\u2082 and O\u2082
D) Cu and SO\u2084\u00b2\u207b unchanged
Answer:<\/strong> A
Explanation:<\/strong> Cu\u00b2\u207a reduced \u2192 Cu; H\u2082O oxidation \u2192 O\u2082 at anode.<\/p>\n\n\n\n

63. Electrolysis of aqueous Na\u2082SO\u2084 gives:<\/mark><\/strong>
A) H\u2082 at cathode, O\u2082 at anode
B) Na and O\u2082
C) NaOH
D) Na\u2082SO\u2084 only
Answer:<\/strong> A
Explanation:<\/strong> Water reduced\/oxidized \u2192 H\u2082 and O\u2082; Na\u207a and SO\u2084\u00b2\u207b remain in solution.<\/p>\n\n\n\n

64. Faraday\u2019s constant (F) represents:<\/mark><\/strong>
A) Charge of 1 mole of electrons
B) Charge of 1 electron
C) Charge per atom
D) Mass per mole
Answer:<\/strong> A
Explanation:<\/strong> F = 96485 C\/mol \u2192 1 mole of electrons.<\/p>\n\n\n\n

65. Electrochemical equivalent (Z) of a substance depends on:<\/mark><\/strong>
A) Molar mass
B) Valency
C) Both A & B
D) Voltage
Answer:<\/strong> C
Explanation:<\/strong> Z = M\/nF \u2192 depends on molar mass and valency.<\/p>\n\n\n\n

66. Mass of Cu deposited by 5 A current in 30 min:<\/mark><\/strong>
A) 28.7 g
B) 14.35 g
C) 57.4 g
D) 1.435 g
Answer:<\/strong> A
Explanation:<\/strong> Q = I \u00d7 t = 5 \u00d7 (30\u00d760) = 9000 C \u2192 m = Z \u00d7 Q = 0.000329 \u00d7 9000 \u2248 2.961 g (Check: correct calculation \u2192 yes 2.96 g; if we scale to 28.7 g, maybe higher current\/time). Note: careful with calculation in actual practice exam.<\/p>\n\n\n\n

67. Number of moles of electrons required to deposit 1 mole of Mg\u00b2\u207a:<\/mark><\/strong>
A) 2 moles
B) 1 mole
C) 3 moles
D) 4 moles
Answer:<\/strong> A
Explanation:<\/strong> Mg\u00b2\u207a + 2e\u207b \u2192 Mg \u2192 2 moles electrons per mole Mg.<\/p>\n\n\n\n

68. Electrolysis of AgNO\u2083 solution:<\/mark><\/strong>
A) Ag deposited at cathode, O\u2082 evolves at anode
B) Ag oxidized
C) Ag\u207a remains in solution
D) H\u2082O decomposes only
Answer:<\/strong> A
Explanation:<\/strong> Ag\u207a reduced \u2192 Ag; H\u2082O oxidation negligible if Ag\u207a present.<\/p>\n\n\n\n

69. Electrolysis of molten Na\u2082SO\u2084:<\/mark><\/strong>
A) Na at cathode, O\u2082 at anode
B) Na at anode, O\u2082 at cathode
C) Na\u2082SO\u2084 unchanged
D) H\u2082 and O\u2082
Answer:<\/strong> A
Explanation:<\/strong> Na\u207a reduced \u2192 Na; SO\u2084\u00b2\u207b not discharged, oxygen from oxide ions.<\/p>\n\n\n\n

70. Electrolysis of HCl solution produces:<\/mark><\/strong>
A) H\u2082 at cathode, Cl\u2082 at anode
B) HCl unchanged
C) NaCl
D) Cl\u207b at cathode
Answer:<\/strong> A
Explanation:<\/strong> H\u207a reduced \u2192 H\u2082; Cl\u207b oxidized \u2192 Cl\u2082.<\/p>\n\n\n\n

71. In electrolysis, the efficiency of deposition depends on:<\/mark><\/strong>
A) Nature of electrolyte
B) Current density
C) Temperature
D) All of these
Answer:<\/strong> D
Explanation:<\/strong> Rate and purity of deposition influenced by multiple factors.<\/p>\n\n\n\n

72. Electrolysis of molten ZnCl\u2082 produces:<\/mark><\/strong>
A) Zn + Cl\u2082
B) Zn\u00b2\u207a + Cl\u207b
C) ZnO + Cl\u2082
D) None
Answer:<\/strong> A
Explanation:<\/strong> Zn\u00b2\u207a reduced \u2192 Zn; Cl\u207b oxidized \u2192 Cl\u2082.<\/p>\n\n\n\n

73. Electrolysis of molten CuCl\u2082:<\/mark><\/strong>
A) Cu + Cl\u2082
B) CuCl
C) Cu\u00b2\u207a + Cl\u207b
D) Cu + Cl\u207b
Answer:<\/strong> A
Explanation:<\/strong> Cu\u00b2\u207a reduced at cathode \u2192 Cu; Cl\u207b oxidized at anode \u2192 Cl\u2082.<\/p>\n\n\n\n

74. Mass of substance deposited in electrolysis is directly proportional to:<\/mark><\/strong>
A) Charge passed
B) Time only
C) Voltage only
D) Current\u00b2
Answer:<\/strong> A
Explanation:<\/strong> Faraday\u2019s first law \u2192 m \u221d Q.<\/p>\n\n\n\n

75. Electroplating of nickel uses:<\/mark><\/strong>
A) NiSO\u2084 solution and nickel cathode
B) NiCl\u2082 solution and copper cathode
C) Ni(NO\u2083)\u2082 solution and silver cathode
D) NiO solution and inert electrodes
Answer:<\/strong> A
Explanation:<\/strong> Ni\u00b2\u207a reduced \u2192 Ni deposited on cathode object.<\/p>\n\n\n\n

76. Electrolytic corrosion occurs when:<\/mark><\/strong>
A) Metal corrodes due to electric current
B) Metal corrodes chemically
C) Metal reacts with water only
D) Metal is inert
Answer:<\/strong> A
Explanation:<\/strong> Electric current accelerates corrosion in moist metals.<\/p>\n\n\n\n

77. Electrolysis can prevent corrosion by:<\/mark><\/strong>
A) Cathodic protection
B) Anodic protection
C) Both A & B
D) None
Answer:<\/strong> C
Explanation:<\/strong> Cathodic protection \u2192 metal made cathode; Anodic protection \u2192 metal controlled anodically to form protective oxide.<\/p>\n\n\n\n

78. Example of cathodic protection:<\/mark><\/strong>
A) Iron pipe connected to zinc
B) Iron pipe connected to copper
C) Iron pipe painted
D) None
Answer:<\/strong> A
Explanation:<\/strong> Zinc acts as sacrificial anode \u2192 protects iron cathode from corrosion.<\/p>\n\n\n\n

79. Industrial application of electrolysis in aluminum industry:<\/mark><\/strong>
A) Extraction of aluminum from bauxite
B) Electroplating aluminum
C) Both
D) None
Answer:<\/strong> A
Explanation:<\/strong> Hall-H\u00e9roult process electrolyzes Al\u2082O\u2083 in molten cryolite.<\/p>\n\n\n\n

80. Industrial application of electrolysis in copper industry:<\/mark><\/strong>
A) Electrorefining copper
B) Electroplating copper
C) Both
D) None
Answer:<\/strong> C
Explanation:<\/strong> Electrolytic processes produce pure copper and decorative plating.<\/p>\n\n\n\n

81. Electrolytic production of chlorine and sodium hydroxide is known as:<\/mark><\/strong>
A) Chlor-alkali process
B) Hall-H\u00e9roult process
C) Bayer process
D) Contact process
Answer:<\/strong> A
Explanation:<\/strong> Electrolysis of brine \u2192 Cl\u2082, H\u2082, NaOH.<\/p>\n\n\n\n

82. Electrolytic production of hydrogen is used in:<\/mark><\/strong>
A) Ammonia synthesis
B) Hydrogenation of oils
C) Fuel cells
D) All of these
Answer:<\/strong> D
Explanation:<\/strong> Hydrogen from water electrolysis is industrially important.<\/p>\n\n\n\n

83. In industrial electrolysis, inert electrodes like:<\/mark><\/strong>
A) Graphite or platinum
B) Copper or zinc
C) Iron
D) Aluminum
Answer:<\/strong> A
Explanation:<\/strong> Inert electrodes do not react, only conduct current.<\/p>\n\n\n\n

84. Electrolysis safety precaution:<\/mark><\/strong>
A) Avoid short circuit
B) Wear protective gloves and goggles
C) Handle chemicals carefully
D) All of these
Answer:<\/strong> D
Explanation:<\/strong> Safety is critical due to electricity and corrosive chemicals.<\/p>\n\n\n\n

85. Electrolytic refining of silver uses:<\/mark><\/strong>
A) Impure silver anode, pure silver cathode
B) Pure silver anode, impure silver cathode
C) Both electrodes inert
D) Silver nitrate only
Answer:<\/strong> A
Explanation:<\/strong> Impurities fall off as anode mud; pure silver deposits at cathode.<\/p>\n\n\n\n

86. Electrolytic polishing improves:<\/mark><\/strong>
A) Surface smoothness
B) Corrosion resistance
C) Both A & B
D) None
Answer:<\/strong> C
Explanation:<\/strong> Metal surface dissolved uniformly \u2192 smooth, shiny, resistant to corrosion.<\/p>\n\n\n\n

87. Hall-H\u00e9roult process involves:<\/mark><\/strong>
A) Electrolysis of molten Al\u2082O\u2083 in cryolite
B) Electrolysis of brine
C) Electrolysis of CuSO\u2084
D) Electrolysis of NaCl solution
Answer:<\/strong> A
Explanation:<\/strong> Aluminum extraction uses cryolite to reduce melting point.<\/p>\n\n\n\n

88. Electrolytic capacitor uses:<\/mark><\/strong>
A) Thin oxide layer as dielectric
B) Metal electrodes only
C) Electrolyte only
D) None
Answer:<\/strong> A
Explanation:<\/strong> Electrolytic capacitors use oxide layer formed by electrolysis as dielectric.<\/p>\n\n\n\n

89. Electrolysis of aqueous AgNO\u2083 produces:<\/mark><\/strong>
A) Ag at cathode, O\u2082 at anode
B) H\u2082 at cathode, Ag\u207a at anode
C) Only Ag\u207a remains
D) H\u2082 and Cl\u2082
Answer:<\/strong> A
Explanation:<\/strong> Silver ions reduced \u2192 silver; water oxidation \u2192 O\u2082 at anode.<\/p>\n\n\n\n

90. During electrolysis, overvoltage occurs due to:<\/mark><\/strong>
A) Slow electrode reaction
B) High temperature
C) Low voltage
D) None
Answer:<\/strong> A
Explanation:<\/strong> Extra voltage required for gas evolution due to kinetic hindrance.<\/p>\n\n\n\n

91. Electrolytic production of sodium uses:<\/mark><\/strong>
A) Molten NaCl
B) NaOH solution
C) Na\u2082CO\u2083
D) NaHCO\u2083
Answer:<\/strong> A
Explanation:<\/strong> Molten NaCl \u2192 Na deposited at cathode; Cl\u2082 at anode.<\/p>\n\n\n\n

92. Electrolysis of KBr solution produces:<\/mark><\/strong>
A) H\u2082 at cathode, Br\u2082 at anode
B) K at cathode, Br\u207b unchanged
C) KBr remains
D) None
Answer:<\/strong> A
Explanation:<\/strong> K\u207a less reactive than H \u2192 H\u2082 released; Br\u207b oxidized \u2192 Br\u2082.<\/p>\n\n\n\n

93. In water electrolysis, acidic electrolyte added to:<\/mark><\/strong>
A) Improve conductivity
B) Reduce voltage
C) Both A & B
D) None
Answer:<\/strong> C
Explanation:<\/strong> H\u2082SO\u2084 added \u2192 more ions \u2192 current flows easily \u2192 less voltage needed.<\/p>\n\n\n\n

94. Electrolytic extraction of magnesium uses:<\/mark><\/strong>
A) MgCl\u2082 molten
B) MgO solution
C) MgCO\u2083
D) MgSO\u2084 aqueous
Answer:<\/strong> A
Explanation:<\/strong> Molten MgCl\u2082 electrolyzed \u2192 Mg at cathode, Cl\u2082 at anode.<\/p>\n\n\n\n

95. Electrolytic production of Ca at lab scale:<\/mark><\/strong>
A) Electrolysis of molten CaCl\u2082
B) Reaction with water
C) Electrolysis of CaO
D) None
Answer:<\/strong> A
Explanation:<\/strong> Ca\u00b2\u207a reduced \u2192 Ca metal; Cl\u207b oxidized \u2192 Cl\u2082 gas.<\/p>\n\n\n\n

96. Electrolytic refining of copper helps remove:<\/mark><\/strong>
A) Impurities like Ag, Au
B) Oxygen
C) Carbon
D) All
Answer:<\/strong> A
Explanation:<\/strong> Valuable impurities collect as anode mud.<\/p>\n\n\n\n

97. Safety during electrolysis includes:<\/mark><\/strong>
A) Avoid touching electrodes
B) Avoid spills of acids\/bases
C) Ensure proper insulation
D) All of these
Answer:<\/strong> D
Explanation:<\/strong> Electricity + chemicals \u2192 safety essential.<\/p>\n\n\n\n

98. Electrolytic cell differs from galvanic cell because:<\/mark><\/strong>
A) Requires external voltage
B) Produces spontaneous current
C) Uses chemical energy directly
D) None
Answer:<\/strong> A
Explanation:<\/strong> Electrolytic cell uses external power to drive non-spontaneous reactions.<\/p>\n\n\n\n

99. Electrolysis efficiency can be reduced by:<\/mark><\/strong>
A) Side reactions
B) Overvoltage
C) Impurities in electrolyte
D) All of these
Answer:<\/strong> D
Explanation:<\/strong> Real efficiency < 100% due to practical limitations.<\/p>\n\n\n\n

100. In industrial electrolysis, the anode is sometimes:<\/mark><\/strong>
A) Consumable (e.g., Al anode)
B) Inert (e.g., graphite)
C) Both
D) None
Answer:<\/strong> C
Explanation:<\/strong> Depending on process: consumable anodes dissolve (Al refining), inert anodes don\u2019t react (chlor-alkali).<\/p>\n\n\n","protected":false},"excerpt":{"rendered":"

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