Sarkari Jobs Pakistan
Download App

Electrochemistry MCQs 2026

48 questions with detailed answers · 17 from past papers · 5 quiz batches available

📚 Chemistry Mcqs 📄 17 Past-Paper Qs ✓ Free · No Login Needed
🎯 Mock Test

Read each question, think about the answer, then click Show Answer to reveal the correct option and explanation. Load 10 at a time so it stays manageable — perfect for one-topic study sessions on the bus or during a break.

Page 1 of 1 Questions 1–10 of 48
  1. Q1 Past Paper · PPSC/FPSC/NTS medium

    The oxidation state of chlorine in NaCl is

    1. A -1
    2. B +1
    3. C 0
    4. D -2
    💡 Explanation:

    Chlorine, being more electronegative, takes on a -1 oxidation state in sodium chloride.

  2. Q2 easy

    In a galvanic cell, electrons flow through the external circuit from the

    1. A Cathode to the anode
    2. B Anode to the cathode
    3. C Salt bridge to the anode
    4. D Cathode to the salt bridge
    💡 Explanation:

    Electrons released at the anode travel through the external wire to the cathode.

  3. Q3 Past Paper · PPSC/FPSC/NTS easy

    The function of a salt bridge in a galvanic cell is to

    1. A Generate current
    2. B Increase voltage
    3. C Maintain electrical neutrality by allowing ion flow between half-cells
    4. D Act as the cathode
    💡 Explanation:

    The salt bridge completes the circuit and keeps both half-cells electrically neutral as ions migrate.

  4. Q4 easy

    In an electrolytic cell, electrical energy is used to

    1. A Generate spontaneous chemical reactions
    2. B Measure pH
    3. C Store heat
    4. D Drive a non-spontaneous chemical reaction
    💡 Explanation:

    Electrolytic cells use an external power source to force a non-spontaneous reaction to occur.

  5. Q5 medium

    In an electrolytic cell, the anode is connected to the ___ terminal of the external battery

    1. A Negative
    2. B Neutral
    3. C Positive
    4. D Ground
    💡 Explanation:

    In electrolysis, the anode is connected to the positive terminal of the external power source.

  6. Q6 Past Paper · PPSC/FPSC/NTS medium

    The oxidation number of oxygen in most compounds is

    1. A +2
    2. B +1
    3. C -2
    4. D -1
    💡 Explanation:

    Oxygen typically has an oxidation state of -2 in most of its compounds.

  7. Q7 medium

    The oxidation number of hydrogen in most compounds is

    1. A -1
    2. B 0
    3. C +1
    4. D +2
    💡 Explanation:

    Hydrogen typically has an oxidation state of +1, except in metal hydrides.

  8. Q8 Past Paper · PPSC/FPSC/NTS medium

    The oxidation number of a free element (uncombined) is always

    1. A Zero
    2. B +1
    3. C -1
    4. D Equal to its group number
    💡 Explanation:

    Atoms in their elemental, uncombined form always have an oxidation number of zero.

  9. Q9 medium

    Electrolysis of molten sodium chloride produces

    1. A Hydrogen and oxygen
    2. B Sodium metal and chlorine gas
    3. C Sodium hydroxide only
    4. D Sodium and oxygen
    💡 Explanation:

    Molten NaCl electrolysis deposits sodium metal at the cathode and releases chlorine gas at the anode.

  10. Q10 medium

    Electroplating uses the principle of

    1. A Combustion
    2. B Neutralization
    3. C Distillation
    4. D Electrolysis to deposit a metal coating on an object
    💡 Explanation:

    Electroplating passes current through an electrolyte to deposit a thin metal layer on an object.

  11. Q11 Past Paper · PPSC/FPSC/NTS medium

    The standard hydrogen electrode (SHE) is assigned a standard reduction potential of

    1. A 0.00 V
    2. B 1.00 V
    3. C -1.00 V
    4. D 2.00 V
    💡 Explanation:

    The SHE is the universal reference electrode, defined as having exactly 0.00 V potential.

  12. Q12 medium

    A metal with a more positive standard reduction potential than hydrogen will

    1. A Displace hydrogen from acids
    2. B Not readily displace hydrogen from dilute acids
    3. C Always corrode faster
    4. D Always be a stronger reducing agent than hydrogen
    💡 Explanation:

    Metals less reactive than hydrogen (higher reduction potential) cannot displace it from dilute acids.

  13. Q13 medium

    According to the electrochemical (activity) series, the most reactive metal listed is generally

    1. A Gold
    2. B Copper
    3. C Silver
    4. D Potassium
    💡 Explanation:

    Potassium sits near the top of the activity series as one of the most reactive metals.

  14. Q14 Past Paper · PPSC/FPSC/NTS medium

    According to the electrochemical series, the least reactive metal (most easily reduced) is generally

    1. A Gold
    2. B Sodium
    3. C Potassium
    4. D Zinc
    💡 Explanation:

    Gold is placed at the bottom of the activity series, being highly resistant to oxidation.

  15. Q15 medium

    A spontaneous redox reaction has a standard cell potential (E°cell) that is

    1. A Zero
    2. B Negative
    3. C Undefined
    4. D Positive
    💡 Explanation:

    A positive E°cell value indicates the reaction is thermodynamically spontaneous.

  16. Q16 medium

    The relationship between Gibbs free energy and cell potential is given by

    1. A ΔG° = nFE°
    2. B ΔG° = −nFE°
    3. C ΔG° = nF/E°
    4. D ΔG° = E°/nF
    💡 Explanation:

    The equation ΔG° = −nFE° links a cell's spontaneity directly to its free energy change.

  17. Q17 Past Paper · PPSC/FPSC/NTS medium

    In a Daniell cell, the two electrodes used are

    1. A Copper and silver
    2. B Zinc and silver
    3. C Copper and gold
    4. D Zinc and copper
    💡 Explanation:

    The classic Daniell cell uses a zinc anode and a copper cathode.

  18. Q18 medium

    In a lead-acid battery (car battery), the electrolyte used is

    1. A Sodium chloride solution
    2. B Potassium hydroxide
    3. C Ammonium chloride paste
    4. D Dilute sulfuric acid
    💡 Explanation:

    Lead-acid batteries use dilute sulfuric acid as their electrolyte.

  19. Q19 medium

    A dry cell (common battery) uses ___ as its electrolyte

    1. A Ammonium chloride paste (or zinc chloride paste)
    2. B Dilute sulfuric acid
    3. C Molten sodium chloride
    4. D Pure water
    💡 Explanation:

    Dry cells use a moist paste of ammonium chloride or zinc chloride as the electrolyte.

  20. Q20 Past Paper · PPSC/FPSC/NTS medium

    Corrosion of iron (rusting) is fundamentally an example of

    1. A Reduction only
    2. B An electrochemical (redox) process
    3. C A physical change only
    4. D Neutralization
    💡 Explanation:

    Rusting involves the oxidation of iron and reduction of oxygen, an electrochemical process.

  21. Q21 medium

    Galvanization protects iron from rusting by coating it with a layer of

    1. A Copper
    2. B Zinc
    3. C Silver
    4. D Gold
    💡 Explanation:

    Galvanization coats iron with a sacrificial layer of zinc to prevent rusting.

  22. Q22 medium

    Which of the following metals would displace copper from copper sulfate solution

    1. A Silver
    2. B Gold
    3. C Mercury
    4. D Zinc
    💡 Explanation:

    Zinc is more reactive than copper, allowing it to displace copper from its salt solution.

  23. Q23 medium

    Faraday's first law of electrolysis states that the mass of a substance deposited at an electrode is directly proportional to the

    1. A Voltage applied
    2. B Resistance of the circuit
    3. C Volume of electrolyte
    4. D Quantity of electric charge passed through the electrolyte
    💡 Explanation:

    Faraday's first law relates deposited mass directly to the total charge passed.

  24. Q24 Past Paper · PPSC/FPSC/NTS medium

    Faraday's second law of electrolysis relates the mass of substances deposited by the same quantity of charge to their

    1. A Equivalent masses
    2. B Boiling points
    3. C Densities
    4. D Colors
    💡 Explanation:

    Faraday's second law states that for a given charge, deposited masses are proportional to equivalent weights.

  25. Q25 medium

    The unit of electric charge used in Faraday's laws, one Faraday, is approximately equal to the charge on

    1. A One mole of electrons (96,500 C)
    2. B One electron only
    3. C One mole of protons only
    4. D One coulomb
    💡 Explanation:

    One Faraday equals the total charge carried by one mole of electrons, about 96,500 coulombs.

  26. Q26 medium

    A fuel cell generates electricity through the electrochemical reaction of

    1. A Coal and oxygen
    2. B Sodium and chlorine
    3. C Hydrogen and oxygen
    4. D Zinc and copper
    💡 Explanation:

    Hydrogen fuel cells generate electricity by combining hydrogen and oxygen, producing water as byproduct.

  27. Q27 Past Paper · PPSC/FPSC/NTS medium

    Which of the following is a secondary (rechargeable) cell

    1. A Dry cell
    2. B Simple voltaic cell
    3. C Daniell cell
    4. D Lead-acid battery
    💡 Explanation:

    Lead-acid batteries can be recharged by reversing the current, making them secondary cells.

  28. Q28 medium

    A primary cell is one that

    1. A Can be recharged indefinitely
    2. B Uses only solid electrolytes
    3. C Cannot be recharged once its reactants are consumed
    4. D Generates no electric current
    💡 Explanation:

    Primary cells are single-use, as their chemical reactants cannot be regenerated by recharging.

  29. Q29 medium

    In an electrolytic cell used for electrorefining of copper, the impure copper is used as the

    1. A Cathode
    2. B Salt bridge
    3. C Electrolyte
    4. D Anode
    💡 Explanation:

    Impure copper is made the anode so it dissolves into solution during electrorefining.

  30. Q30 Past Paper · PPSC/FPSC/NTS medium

    During electrorefining of copper, pure copper is deposited at the

    1. A Cathode
    2. B Anode
    3. C Salt bridge
    4. D Electrolyte solution only
    💡 Explanation:

    Copper ions from solution are reduced and deposited as pure copper at the cathode.

  31. Q31 medium

    The SI unit of electrode potential is the

    1. A Ampere
    2. B Coulomb
    3. C Volt
    4. D Ohm
    💡 Explanation:

    Electrode potential, a measure of electrical potential difference, is expressed in volts.

  32. Q32 hard

    The number of electrons transferred when Fe2+ is oxidized to Fe3+ is

    1. A 2
    2. B 3
    3. C 1
    4. D 0
    💡 Explanation:

    Fe2+ loses exactly one electron to become Fe3+.

  33. Q33 hard

    In the reactivity series, metals above hydrogen can generally

    1. A Not react with dilute acids
    2. B Displace hydrogen from dilute acids
    3. C Only react with bases
    4. D React only with water, never acids
    💡 Explanation:

    Metals more reactive than hydrogen can displace it from dilute acids, releasing hydrogen gas.

  34. Q34 hard

    Which of the following best defines an electrolyte

    1. A A substance that never conducts electricity
    2. B A metal that conducts electricity in solid form
    3. C A substance that conducts electricity in molten or dissolved (aqueous) form due to ion movement
    4. D A gas that conducts electricity when heated
    💡 Explanation:

    Electrolytes conduct electric current through the movement of ions when molten or dissolved.

  35. Q35 Past Paper · PPSC/FPSC/NTS hard

    Which of the following processes occurs at the cathode in any electrochemical cell (galvanic or electrolytic)

    1. A Oxidation always
    2. B Loss of electrons
    3. C Formation of anions only
    4. D Reduction (gain of electrons)
    💡 Explanation:

    By definition, reduction always occurs at the cathode in both galvanic and electrolytic cells.

  36. Q36 hard

    The standard electrode potential of a half-cell is measured relative to the

    1. A Zinc electrode
    2. B Copper electrode
    3. C Calomel electrode only
    4. D Standard hydrogen electrode
    💡 Explanation:

    All standard electrode potentials are conventionally measured against the standard hydrogen electrode.

  37. Q37 hard

    A cell in which the overall reaction produces electrical energy from a spontaneous chemical reaction is called a

    1. A Galvanic (voltaic) cell
    2. B Electrolytic cell
    3. C Concentration gradient only
    4. D Fuel-only cell
    💡 Explanation:

    Galvanic cells convert the energy of a spontaneous redox reaction directly into electrical energy.

  38. Q38 Past Paper · PPSC/FPSC/NTS hard

    In the electrolysis of aqueous sodium chloride (brine), the gas produced at the anode is

    1. A Chlorine
    2. B Hydrogen
    3. C Oxygen
    4. D Nitrogen
    💡 Explanation:

    Chloride ions are oxidized at the anode during brine electrolysis, releasing chlorine gas.

  39. Q39 hard

    In the electrolysis of aqueous sodium chloride (brine), the gas produced at the cathode is

    1. A Chlorine
    2. B Oxygen
    3. C Hydrogen
    4. D Nitrogen
    💡 Explanation:

    Water is reduced at the cathode during brine electrolysis, releasing hydrogen gas.

  40. Q40 hard

    A concentration cell generates electric current due to a difference in the

    1. A Electrode material only
    2. B Concentration of the electrolyte solutions in the two half-cells
    3. C Temperature of the electrodes
    4. D Color of the solutions
    💡 Explanation:

    Concentration cells use identical electrodes but different electrolyte concentrations to generate a potential difference.

  41. Q41 Past Paper · PPSC/FPSC/NTS hard

    Anodizing is an electrolytic process most commonly used to increase the thickness of the natural oxide layer on

    1. A Aluminum
    2. B Iron
    3. C Copper
    4. D Zinc
    💡 Explanation:

    Anodizing is widely applied to aluminum to build a thicker, more protective oxide coating.

  42. Q42 medium

    The process of purifying an impure metal using electrolysis is called

    1. A Galvanization
    2. B Anodizing
    3. C Electrorefining
    4. D Electroplating
    💡 Explanation:

    Electrorefining uses electrolysis to purify an impure metal, depositing pure metal at the cathode.

  43. Q43 easy

    Oxidation is defined as the process involving

    1. A Gain of electrons
    2. B Loss of electrons
    3. C Gain of protons
    4. D Loss of protons
    💡 Explanation:

    Oxidation is defined as the loss of one or more electrons by a substance.

  44. Q44 Past Paper · PPSC/FPSC/NTS easy

    Reduction is defined as the process involving

    1. A Loss of electrons
    2. B Gain of electrons
    3. C Loss of protons
    4. D Gain of neutrons
    💡 Explanation:

    Reduction involves gaining one or more electrons.

  45. Q45 Past Paper · PPSC/FPSC/NTS easy

    A redox reaction always involves

    1. A Only oxidation
    2. B Both oxidation and reduction occurring simultaneously
    3. C Only reduction
    4. D Neither oxidation nor reduction
    💡 Explanation:

    Electrons lost in oxidation must be gained somewhere, so oxidation and reduction always occur together.

  46. Q46 easy

    The substance that gets oxidized in a redox reaction and causes reduction of another substance is called the

    1. A Oxidizing agent
    2. B Catalyst
    3. C Reducing agent
    4. D Electrolyte
    💡 Explanation:

    The reducing agent donates electrons, itself becoming oxidized, while reducing another species.

  47. Q47 Past Paper · PPSC/FPSC/NTS easy

    The substance that gets reduced and causes oxidation of another substance is called the

    1. A Reducing agent
    2. B Catalyst
    3. C Oxidizing agent
    4. D Electrode
    💡 Explanation:

    The oxidizing agent accepts electrons, itself becoming reduced, while oxidizing another species.

  48. Q48 easy

    In an electrochemical (galvanic/voltaic) cell, oxidation occurs at the

    1. A Anode
    2. B Cathode
    3. C Salt bridge
    4. D External wire only
    💡 Explanation:

    By convention, oxidation always takes place at the anode of an electrochemical cell.

More Chemistry Mcqs Topics

📖
Atomic Structure 50 MCQs
→ 📖
Periodic Table and Periodicity 50 MCQs
→ 📖
Chemical Bonding 50 MCQs
→ 📖
Stoichiometry and Chemical Calculations 50 MCQs
→ 📖
Gases and Gas Laws 50 MCQs
→ 📖
Thermochemistry 50 MCQs
→

See all Chemistry Mcqs topics →

Get instant alerts & apply faster — install the free app Install App