For a galvanic cell using Fe | Fe^2+(1.0 M) and Pb | Pb^2+ (1.0 M) half-cells, w

Question

For a galvanic cell using Fe | Fe^2+(1.0 M) and Pb | Pb^2+ (1.0 M) half-cells, which of the following statements is correct? Fe2^+(aq) + 2e^- rightarrow Fe(s); E degree = -0.41 V Pb^2+ (aq) + 2e^- rightarrow Pb(s); E degree = -0.13 V a. The iron electrode is the cathode. b. When the cell has completely discharged, the concentration of Pb^2+ is zero. c. The mass of the iron electrode increases during discharge. d. The concentration of Pb^2+ decreases during discharge. e. Electrons leave the lead electrode to pass through the external circuit during discharge

Explanation / Answer

a) This is incorrect. Cathode is the terminal where reduction takes place.

Standard reduction potential of iron is -0.41V which is less than that of lead i.e. -0.13 V

Therefore, lead is more likely to be reduced and hence will act as cathode.

b) It is correct because the lead ions are reduced completely by the electrons coming from anode.

c) This is incorrect. As the iron electrode is oxidizing it loses electrons, releasing the ions into the solution.

This reduces the size of iron electrode during discharge.

d) Again incorrect as Pb2+ ions are reduced to form Pb and precipitate out, and Pb2+ concentraion decreases.

e) Incorrect. Loss of electron i.e. oxidation, takes place at anode electrode which is iron. These electrons pass through the external circuit and reach the cathode which is the Pb electrode. This constitutes the current.

Related Questions

Navigate

• Browse (All)
• Browse F
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.