Chapter 19, Problem 19.76QP

Interpretation Introduction

Interpretation:

The free energy change of given voltaic cell should be calculated by using standard reduction potentials.

Concept introduction:

Cell potential (EMF):

The maximum potential difference between two electrodes in the voltaic cell is known as cell potential.

If standard reduction potentials of electrodes are given the cell potential (EMF) is given by,

${\text{E}}_{\text{cell}}\text{=}{\text{E}}_{\text{cathode}}{\text{-E}}_{\text{anode}}$

Where,

$\begin{array}{l}{\text{E}}_{\text{cathode}}\text{is}\text{the}\text{reduction}\text{half}\text{cell potential}\\ {\text{E}}_{\text{anode}}\text{is}\text{the}\text{oxidation}\text{half}\text{cell potential}\end{array}$

Free energy change:

In thermodynamics the cell potential is known as  maximum work of the cell and it is equal to free energy change of the cell and it is given by,

$\text{ΔG}\text{=}{\text{-nFE}}_{\text{cell}}$

Where,

$\begin{array}{l}\text{ΔG}\text{is}\text{free}\text{energy}\text{change}\\ \text{n}\text{is}\text{number}\text{of}\text{electron}\text{transferred}\\ \text{F}\text{is}\text{faraday constant}\\ {\text{E}}_{\text{cell}}\text{is}\text{cell potential}\end{array}$