Chapter 19, Problem 19.84QP

Interpretation Introduction

Interpretation:

The equilibrium constant of given cell reaction 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,

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

Equilibrium constant ${\text{K}}_{\text{c}}$:

The relationship between equilibrium constant and cell potential (EMF) is given by below equation,

${\text{E}}_{\text{cell}}\text{=}\frac{\text{RT}}{\text{nF}}{\text{lnK}}_{\text{c}}$

Where,

$\begin{array}{l}{\text{K}}_{\text{c}}\text{is}\text{equilibrium constant}\\ \text{n}\text{is}\text{number}\text{of}\text{electron}\text{transferred}\\ \text{F}\text{is}\text{faraday constant}\\ {\text{E}}_{\text{cell}}\text{is}\text{cell potential}\\ \text{R}\text{is }\text{gas}\text{constant(8}\text{.314J/mol}\text{K)}\\ \text{T}\text{is}\text{temprrature}\text{(25°C)}\end{array}$