Answer to Question #350009 in General Chemistry for Meg

Question

Which of the following cells will produce the highest voltage? SHOW YOUR WORK.

a. Mn I Mn^2+ II Zn^2+ I Zn

b. Zn I Zn^2+ II Ni^2+ I Ni

c. Ni I Ni^2+ II Cu^2+ I Cu

Solve separately then write which one will produce the highest voltage.

Answer 1

The overall cell potential can be calculated by using the equation E₀cell=E₀red−E₀oxid.

a.

Mn - 2e^- => Mn²⁺ E₀ = -1,05 V

Zn²⁺ + 2e^- => Zn E₀ = -0,76 V

Mn + ZnCl₂ => MnCl₂ + Zn E₀ = - 0,29

b.

Zn - 2e^- => Zn²⁺ E₀ = -0,76

Ni²⁺ + 2e^- => Ni E₀ = -0,23

NiCl₂ + Zn => ZnCl₂ + Ni E₀ = -0,53

c.

Ni - 2e^- => Ni²⁺ E₀ = -0,23

Cu²⁺ -2e^- = Cu E₀ = 0,34

CuCl₂ + Ni = NiCl₂ + Cu E₀ = -0,57

Answer: c.