Close Menu
    Facebook X (Twitter) Instagram
    ScienceMotive
    • Class 9
      • Matter in Our Surroundings
      • Is Matter Around Us Pure
      • Atoms and Molecules
      • Structure of the Atom
      • The Fundamental Unit of Life
    • Class 10
      • Chapter 1: Chemical Reactions and Equations
      • Chapter 2: Acids, Bases & Salts
      • Chapter 3: Metals & Non-Metals
      • Chapter 4: Carbon and its Compounds
      • Chapter 5: Periodic Classification of Elements
      • Chapter 6: Life Processes
      • Chapter 7: Control and Coordination
      • Chapter 8: How Do Organisms Reproduce?
      • Chapter 9: Heredity and Evolution
      • Chapter 10: Light – Reflection and Refraction
      • Chapter 11: Human Eye and the Colourful World
      • Chapter 12: Electricity
      • Chapter 13: Magnetic Effects of Electric Current
      • Chapter 14: Sources of Energy
      • Chapter 15: Our Environment
      • Chapter 16: Management of Natural Resources
    • Class 11
      • Chemisrty 11
        • Chapter – 1 Some Basic Concepts of Chemistry
        • Chapter – 2 Structure Of Atom
        • Chapter – 3 Classification of Elements and Periodicity in Properties
        • Chapter – 4 Chemical Bonding and Molecular Structure
        • Chapter – 5 States of Matter
        • Chapter – 6 Thermodynamics
        • Chapter – 7 Equilibrium
        • Chapter – 8 Redox Reaction
        • Chapter – 10 s-Block Elements
        • Chapter – 13 Hydrocarbons
    • Class 12
      • Chemistry 12
        • The Solid State
        • Solutions
        • Electrochemistry
        • Chemical Kinetics
        • Surface Chemistry
        • p – Block Elements
        • d & f Block Elements
        • Coordination Compounds
        • Haloalkanes and Haloarenes
        • Alcohols, Phenols and Ethers
        • Aldehydes, Ketones and Carboxylic Acids
        • Amines
        • Biomolecules
        • Polymers
        • Chemistry in Everyday Life
    • Practice Questions
      • +1
      • +2
    • Test Series
      • Class 9 Test Series
      • Class 10 Test Series
      • Class 11 Test Series
      • Class 12 Test Series
    • World
      • Current Affairs
      • General Knowledge
    ScienceMotive
    Home » Electrochemistry Class 12 NCERT Exercise Solutions

    Electrochemistry Class 12 NCERT Exercise Solutions

    Dr. Vikas JasrotiaBy Dr. Vikas JasrotiaJuly 16, 2021No Comments
    Share
    Facebook WhatsApp Telegram Twitter Email

    Electrochemistry Class 12 NCERT Exercise Solutions

    Que 1. Arrange the following metals in the order in which they displace each other from their salts. Al, Cu, Fe, Mg, and Zn
    Ans 1. The order in which metals displace each other from the solution of their salts can be given with the help of their standard electrode potential. Since magnesium has the least standard electrode potential so it is the most strong reducing agent. So the required order we get is Mg, Al, Zn, Fe, Cu

    Que 2. Given the standard electrode potentials, K+/K=-2. 93 V, Ag+/Ag = 0.80 V, Hg2+/Hg = 0.79V, Mg2+/Mg = -2.37V, Cr3+/Cr = 0.74V. Arrange these metals in their increasing order of reducing power.
    Ans 2. Elements with reducing power or reducing agents have least/minimum standard electrode potential i.e., reducing power increases with a decrease in standard electrode potential. So the result obtained is K > Mg > Cr > Hg > Ag.

    Que 3. Depict the galvanic cell in which the reaction
    Zn(s) + 2Ag+(aq) → 7M2+(aq) + 2Ag (s) takes place. Further show:
    (i) Which of the electrode is negatively charged?
    (ii) The carriers of the current in the cell.
    (iii) Individual reaction at each electrode.
    Ans 3. (i) The galvanic cell of the given reaction is depicted below :-
    Zn (s) | Zn +2 (aq) || Ag + (aq) | Ag (s)
    Clearly Zn electrode is negatively charged.
    (ii) The carriers of current in the cell are ions. So current flows from silver to zinc in the external circuit.
    (iii)  At anode: Zn(s) → Zn2+(aq) + 2e–
    At cathode: 2Ag+(aq) + 2e– → 2Ag(s)

    Electrochemistry Class 12 NCERT Exercise Solutions

    Que 4. Calculate the standard cell potentials of the galvanic cells in which the following reactions take place.
    (a) 2Cr + 3Cd2+ → 2Cr3+ + 3Cd
    Given E0 Cr3+/Cr = -0.74V, E0 Cd2+/Cd = -0.40V
    (b) Fe2+ + Ag+ → Fe3+ + Ag
    Given E0Ag+/Ag = 0.80V, E0Fe+3/Fe = 0.77V
    Also, calculate ∆G° and equilibrium constant for the reaction.
    Ans 4. Eø Cr3+ / Cr  = – 0.74 V
       Eø Cd2+ / Cd  = – 0.40 V
    The galvanic cell of the given reaction is depicted as:
    Cr/Cr3+//Cd2+/Cd
    Now, the standard cell potential is
    Eø  = EøR  – EøL
    = -0.40 – (-0.74) = + 0.34 V
    ΔrGø = –nFEøcell
    In the given equation,
    n = 6
    F = 96487 C mol – 1
    Eøcell = +0.34 V
    Then, ΔGø  = – 6 × 96487 C mol – 1 × 0.34 V
    = – 196833.48 CV mol – 1
    = – 196833.48 J mol – 1
    = – 196.83 kJ mol – 1
    Again,
    ΔGø = – RT ln Kc
    logKc = -ΔGø/2.303RT

    = 34.496
    K = antilog (34.496)
    = 3.13 × 1034
     
    (ii) Eø Fe3+ / Fe2+  =  0.77 V
       Eø Ag+ / Ag        =  0.80 V
    The galvanic cell of the given reaction is depicted as:
    Fe+2/Fe3+//Ag+/Ag
    Now, the standard cell potential is
    Eø  = EøR  – EøL
           = 0.80 – 0.77  = 0.03 V
    Here, n = 1.
    Then, ΔGø = –nFEøcell
    = – 1 × 96487 C mol – 1 × 0.03 V
    = – 2894.61 J mol – 1
    = – 2.89 kJ mol – 1
    Again, ΔGø = – 2.303 RT ln K

    = 0.5073
    K = antilog (0.5073) = 3.2

    Electrochemistry Class 12 NCERT Exercise Solutions

    Que 5. Write the Nernst equation and emf of the following cells at 298 K:
    (i) Mg(s) | Mg2+(0.001M) || Cu2+(0.0001 M) | Cu(s)
    (ii) Fe(s) | Fe2+(0.001M) || H+(1M)|H2(g)(1bar) | Pt(s)
    (iii) Sn(s) | Sn2+(0.050 M) || H+(0.020 M) | H2(g) (1 bar) | Pt(s)
    (iv) Pt(s) | Br2(l) | Br−(0.010 M) || H+(0.030 M) | H2(g) (1 bar) | Pt(s).
    Ans 5. (i) Mg(s) +Cu2+(aq)↔ Mg2+(aq) + Cu(s)
    Nernst equation

    There are two electron are transferring so that n = 2
    E°cell = E°right – E°left
    E° cell = + 0.34 – (–2.37)V
    E° cell = +2.71V
    Concentration of solid substance is 1 always so that [Mg] = [Cu] =1

    (ii) Fe(s) +2H+(aq)↔ Fe2+(aq) + H2(g)
    Nernst equation

    There are two electrons are transferring so that n = 2
    E°cell = E°right – E°left
    E°cell =0– (–0.44)V
    E°cell =+0.44 V
    Concentration of solid substance is 1 always so that [Fe] = [H2] =1
                                                                                                                                                                                                                              
    (iii) Sn(s) +2H+(aq)↔ Sn2+(aq) + H2(g)
    Nernst equation

    There are two electrons are transferring so that n = 2
    E°cell  = E°right – E°left
    E° cell  = 0– (–0.14)V
    E° cell  =+0.14 V
    Concentration of solid substance is 1 always so that [Sn] = [H2] =1

    (iv) 2Br–(aq) + 2H+(aq)↔ Br2(l) + H2(g)
    Nernst equation

    There are two electron are transferring so that n = 2
    E°cell  =  E°right – E°left
    E° cell  = 0– (1.08)V

    E° cell  = –1.08V
    Concentration of solid substance is 1 always so that [Br2] = [H2] =1
     

    Electrochemistry Class 12 NCERT Exercise Solutions

    Advertisement
    Electrochemistry Class 12 NCERT Exercise Solutions
    Share. Facebook Twitter Pinterest LinkedIn Tumblr Email
    Dr. Vikas Jasrotia
    • Website

    Related Posts

    Solid State Chemistry Class 12 Notes PDF Download

    September 10, 2024

    CBSE Sample Paper Session 2022-23 (Chemistry) PDF

    September 16, 2022

    Haloalkanes and Haloarenes Class 12 – Questions & Answers

    August 2, 2022
    Leave A Reply Cancel Reply

    READ ALSO

    Gravitation Class 9 Notes

    December 5, 2024

    Class 11 Chemistry Half Yearly Question Paper

    September 30, 2024

    Solid State Chemistry Class 12 Notes PDF Download

    September 10, 2024

    Redox Reaction

    June 13, 2024
    Class 9

    Gravitation Class 9 Notes

    By Dr. Vikas JasrotiaDecember 5, 2024

    Gravitation Class 9 Notes Gravitation Class 9 Notes Gravitation According to Newton, every object in…

    +1

    Class 11 Chemistry Half Yearly Question Paper

    By Dr. Vikas JasrotiaSeptember 30, 2024

    Class 11 Chemistry Half Yearly Question Paper Class 11 Chemistry Half Yearly Question Paper Time…

    +2

    Solid State Chemistry Class 12 Notes PDF Download

    By Dr. Vikas JasrotiaSeptember 10, 2024

    Solid State Chemistry Class 12 Notes PDF Download In our day-to-day life solids play…

    Advertisement
    Advertisement
    Facebook X (Twitter) Instagram Pinterest YouTube
    • Disclaimer
    • Contact Us
    • Privacy Policy 
    • Terms and Conditions
    © 2025 All Rights Reserved ScienceMotive.

    Type above and press Enter to search. Press Esc to cancel.