Chapter 20, Problem 78A

a.

Interpretation Introduction

Interpretation:

Identify the cathode.

Concept introduction:

In a voltaic cell, the electrode which undergoes reduction is called cathode.

Answer to Problem 78A

The copper cylinder will act as cathode.

Explanation of Solution

The reduction potential of copper is positive when compared to iron so it will get reduced more easily and act as cathode.

b.

Interpretation Introduction

Interpretation:

Identify the anode.

Concept introduction:

In a voltaic cell, the electrode which undergoes oxidation is called cathode.

Answer to Problem 78A

The iron bar will act as cathode.

Explanation of Solution

The reduction potential of iron is negative when compared to copper so it will get oxidized more easily and act as anode.

c.

Interpretation Introduction

Interpretation:

Calculate the standard potential of battery.

Concept introduction:

In a voltaic cell, the standard potential is the sum of potential of its respective half cells.

Answer to Problem 78A

The standard potential of this battery is $0.78V$. $0.96V$ 0.52+0.44

Explanation of Solution

Reaction of oxidation half cell:

$Fe\to F{e}^{2+}+2e^{-}\text{ E}°\text{=+0}\text{.44V}$

Reaction of reduction half cell:

$C{u}^{2+}+2e^{-}\to Cu\text{ E}°\text{=+0}\text{.34V}$

Standard potential of battery:

$\begin{array}{l}\text{E}{°}_{cell}\text{=+0}\text{.44+0}\text{.34}\\ \text{E}{°}_{cell}=0.78V\end{array}$