Class 12 Chemistry
Chapter 3 – Electrochemistry
Magical Series Assignment 1
Q.1. Depict the galvanic cell in which the reaction
Zn(s) + 2Ag+(aq) → Zn2+(aq) + 2Ag(s) takes place.
(i) Which of the electrode is negatively charged?
(ii) The carriers of the current in the cell.
(iii) Individual reaction at each electrode.
Q.2. Equilibrium constant (KC) for the given cell reaction is 10. Calculate Eocell.
A(s) + B2+(aq) ⇌ A2+(aq) + B(s)
Q.3. What is the necessity to use a salt bridge in a Galvanic cell?
Q.4. Two half–reactions of an electrochemical cell are given below:
MnO4–(aq) + 8H+(aq) + 5e– → Mn2+(aq) + 4H2O(l); Eo = +1.51 V
Sn2+(aq) → Sn4+(q) + 2e–; Eo = +0.15 V
Construct the redox equation from the standard potential of the cell and predict if the reaction is reactant favoured or product favoured.
Q.5. Define electrochemical cell. What happens if external potential applied becomes greater than Eocell of electrochemical cell?
Q.6. Represent the galvanic cell in which the reaction
Zn(s) + Cu2+(aq) → Zn2+(aq) + Cu(s) takes place.
Q.7. Given that the standard electrode potential (Eo) of metals are:
K+/K = –2.93 V, Ag+/Ag = 0.80 V, Cu2+ /Cu = 0.34 V, Mg2+/Mg = –2.37 V, Cr3+/Cr = –0. 74 V, Fe2+ /Fe = –0.44 V
Arrange these metals in an increasing order of their reducing power.
Q.8. A cell is prepared by dipping copper rod in 1 M copper sulphate solution and zinc rod in 1 M zinc sulphate solution. The standard reduction potential of copper and zinc are 0.34 V and –0.76 V respectively.
(i) What will be the cell reaction?
(ii) What will be the standard electromotive force of the cell?
(iii) Which electrode will be positive?
Q.9. Calculate ∆rGo for the reaction:
Mg(s) + Cu2+(aq) → Mg2+(aq) + Cu(s)
Given Eocell = +2.71 V, 1 F = 96500 C mol–1.
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