Chapter 21, Problem 21.134MP

(a)

Interpretation Introduction

Interpretation:

The value of x in iron oxide ${\text{Fe}}_{\text{x}}\text{O}$ has to be given.

(b)

Interpretation Introduction

Interpretation:

The average oxidation state of iron has to be calculated.

(c)

Interpretation Introduction

Interpretation:

The percentage of ${\text{Fe}}^{\text{3+}}$ ions in wustite has to be calculated.

Concept introduction:

Wustite:

Wustite is iron oxide with empirical formula of ${\text{Fe}}_{\text{x}}\text{O}$ .  The value of x is slightly less than one.  Iron has two oxidation state of $\text{+2}\text{and}\text{+3}$.  But the major form of iron exist as ${\text{Fe}}^{\text{2+}}$ ion.  The stoichiometry shows there is $1:1$ ratio of iron and oxygen.

(d)

Interpretation Introduction

Interpretation:

The angle at which atoms meet in face centered cubic unit cell has to be calculated.

Concept introduction:

Braggs law:

$\text{nλ}\text{=}\text{2dsinθ}$

Where,

n is order of diffraction.

d is lattice spacing

$\text{λ}$ is wavelength.

(e)

Interpretation Introduction

Interpretation:

The doping of ${\text{Fe}}^{\text{3+}}$ in iron oxide leads to n-type or p-type semiconductor has to be explained.

Concept introduction:

Semiconductor: A material which can conduct electricity in range between a metal and an insulator is known as semiconductor.  Addition of small amount of impurities increases conductivity of semiconductor and the process is known as doping.  n-type and p-type are two types of doped semiconductors.

n-type: This is a type of doped semiconductor in which many free electrons are present in conduction band.

p-type: This is a type of doped semiconductor in which holes are present in valence band.