Chapter 19, Problem 49A

Interpretation Introduction

(a)

Interpretation:

The oxidation number of each element in $Au{\left(Se{O}_4\right)}_3$ needs to be determined.

Concept introduction:

Oxidation number: It is defined as charge the atom would have if electrons are not shared but transfer completely.

Answer to Problem 49A

+5

Explanation of Solution

Oxidation number of $AuinAu{\left(Se{O}_4\right)}_3(gold(III)selenate)=+3$

Oxidation number of $O=-2$

The oxidation number of $Se$ is calculated as:

$\begin{array}{c}+3+3\left[x+\left(-2\times 4\right)\right]=0\\ 3+3x-24=0\\ 3x-21=0\\ 3x=21\\ x=7\end{array}$

Interpretation Introduction

(b)

Interpretation:

The oxidation number of each element in $Ni{\left(CN\right)}_2$ needs to be determined.

Concept introduction:

Oxidation number: It is defined as charge the atom would have if electrons are not shared but transfer completely.

Answer to Problem 49A

+4

Explanation of Solution

Oxidation number of $NiinNi{\left(CN\right)}_2(nickel(II)cyanide)=+2$

Oxidation number of $N=-3$

The oxidation number of $C$ is calculated as:

$\begin{array}{c}+2+2\left[x-3\right]=0\\ 2+2x-6=0\\ 2x-4=0\\ 2x=4\\ x=2\end{array}$