CBSE Class 12 Chemistry Electrochemistry Worksheet Set B

Question. The standard electrode potential (E°) values of Al³⁺/Al, Ag⁺/Ag, K⁺/K and Cr³⁺/Cr are –1.66 V, 0.80 V, –2.93 V and –0.74 V, respectively. The correct decreasing order of reducing power of the metal is
(a) Ag > Cr > Al > K
(b) K > Al > Cr > Ag
(c) K > Al > Ag > Cr
(d) Al > K > Ag > Cr

Question. A button cell used in watches function as following :
Zn_(s) + Ag₂O(s) + H₂O(l) ⇌ 2Ag(s) + Zn²⁺_(aq) + 2OH^–_(aq)
If half cell potentials are
Zn²⁺_(aq) + 2e^– → Zn(s); E° = – 0.76 V
Ag₂O_(s) + H₂O(l) + 2e^– → 2Ag_(s) + 2OH–(aq); E° = 0.34 V
The cell potential will be
(a) 0.84 V
(b) 1.34 V
(c) 1.10 V
(d) 0.42 V 

Question. Standard reduction potentials of the half reactions are given below :
F_2(g) + 2e^– → 2F–_(aq) ; E° = + 2.85 V
Cl_2(g) + 2e^– → 2Cl^–_(aq) ; E° = + 1.36 V
Br₂(l) + 2e– → 2Br^–_(aq) ; E° = + 1.06 V
I₂(s) + 2e– → 2I^–_(aq) ; E° = + 0.53 V
The strongest oxidising and reducing agents respectively are
(a) F₂ and I–
(b) Br₂ and Cl^–
(c) Cl₂ and Br–
(d) Cl₂ and I₂

Question. Standard electrode potentials of three metals X, Y and Z are –1.2 V, + 0.5 V and – 3.0 V respectively.
The reducing power of these metals will be
(a) Y > Z > X
(b) Y > X > Z
(c) Z > X > Y
(d) X > Y > Z 

Question. Standard electrode potential for Sn⁴⁺/Sn²⁺ couple is +0.15 V and that for the Cr³⁺/Cr couple is –0.74 V. These two couples in their standard state are connected to make a cell. The cell potential will be
(a) + 1.19 V
(b) + 0.89 V
(c) + 0.18 V
(d) + 1.83 V

Question. A solution contains Fe²⁺, Fe³⁺ and I– ions. This solution was treated with iodine at 35°C. E° for Fe³⁺/Fe²⁺ is + 0.77 V and E° for I₂/2I– = 0.536 V. The favourable redox reaction is
(a) I₂ will be reduced to I–
(b) there will be no redox reaction
(c) I^– will be oxidised to I₂
(d) Fe²⁺ will be oxidised to Fe³⁺. 

Question. Consider the following relations for emf of an electrochemical cell
(i) EMF of cell = (Oxidation potential of anode) –(Reduction potential of cathode)
(ii) EMF of cell = (Oxidation potential of anode) + (Reduction potential of cathode)
(iii) EMF of cell = (Reductional potential of anode)+ (Reduction potential of cathode)
(iv) EMF of cell = (Oxidation potential of anode) – (Oxidation potential of cathode)
Which of the above relations are correct?
(a) (iii) and (i)
(b) (i) and (ii)
(c) (iii) and (iv)
(d) (ii) and (iv)

Question. On the basis of the following E° values, the strongest oxidizing agent is
[Fe(CN)₆]₄– → [Fe(CN)₆]₃– + e– ; E° = –0.35 V
Fe²⁺ → Fe³⁺ + e– ; E° = –0.77 V
(a) Fe³⁺
(b) [Fe(CN)₆]^3–
(c) [Fe(CN)₆]^4–
(d) Fe²⁺