Question

Which of the following is the correct cell diagram for the reaction:

2 Fe²⁺_(aq) + Cl_{2 (g)}  ??> 2 Fe³⁺_(aq) + 2 Cl^–_(aq)

Fe³⁺(1.0M) | Fe²⁺(1.0M) || Cl₂(g) | Cl^–(1.0M)

Fe(s) | Fe³⁺(1.0M), Fe²⁺(1.0M) || Cl₂(g) | Cl^–(1.0M) | Pt(s)

Pt(s) , Fe³⁺(1.0M), Fe²⁺(1.0M) || Cl₂(g), Cl^–(1.0M) | Pt(s)

Fe(s) | Fe³⁺(1.0M) | Fe²⁺(1.0M) || Cl₂(g) | Cl^–(1.0M) | Pt(s)

Pt(s) | Fe²⁺(1.0M), Fe³⁺(1.0M) || Cl₂(g) | Cl^–(1.0M) | Pt(s)

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Based on the following standard reduction potentials:

Fe³⁺ + e^–  ? Fe²⁺                                        +0.77 V

MnO₄^– + 8 H⁺ + 5 e^–  ? Mn²⁺ + 4 H₂O    +1.51 V

Zn²⁺ + 2e^–  ? Zn                                       –0.76 V

V³⁺ + e^–  ? V²⁺                               –0.26 V

Br₂ + 2 e^–  ? 2 Br^–                                    +1.09 V

       which of the above is the weakest oxidizing agent?

		Zn2+
		V3+
		Fe3+
		Br2
		MnO4–

Answer 1

Ans 1

The two half cell reactions are

Oxidation reaction occurs at anode

2 Fe2+(aq) = 2 Fe3+(aq) + 2e-

Reduction reaction occurs at cathode

Cl2 (g) + 2e- = 2 Cl-(aq)

Standard cell notation

Oxidation reaction at anode || reduction reaction at cathode

Pt(s) | Fe2+(1.0M), Fe3+(1.0M) || Cl2(g) | Cl–(1.0M) | Pt(s)

Option E is the correct answer

Ans 2

Lower the value of standard reduction potential of cell, weaker the Oxidizing agent.

Among the given choices

Lowest standard potential = - 0.76 V

Zn2+ is weakest oxidizing agent