Chapter 19.7, Problem 19.3CC

(a)

Interpretation Introduction

Interpretation:

The sign of $\text{ΔG°}$ given cell should be explained.

Concept introduction:

Cell potential (EMF):

The maximum potential difference between two electrodes of 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,

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

(b)

Interpretation Introduction

Interpretation:

The way of concentration change to make a cell potential get reduced are should be explained.

Nernst equation:

The relationship between standard cell potential and cell potential at non standard conditions and the reaction quotient are given by Nernst equation it is,

${\text{E}}_{\text{cell}}\text{=}{\text{E°}}_{\text{cell}}\text{-}\frac{\text{2}\text{.303}\text{RT}}{\text{nF}}\text{logQ}$

Where,

$\begin{array}{l}{\text{E}}_{\text{cell}}\text{ is}\text{cell potential}\\ {\text{E°}}_{\text{cell}}\text{is}\text{standard cell potential}\\ \text{R}\text{is}\text{gas}\text{constant}\\ \text{T}\text{is}\text{temperature}\\ \text{Q}\text{is}\text{reaction quotient}\end{array}$