Chapter 15, Problem 15.41FU

(a)

Interpretation Introduction

Interpretation:

The reactant which is oxidized and the reactant which is reduced should be identified.

Concept Introduction:

The chemical reaction in which both oxidation and reduction process takes place is known as redox reaction. In this reaction, transfer of electrons takes place among the elements.

Oxidation is the process in which either there is loss of electrons, oxidation number increases, or loss of hydrogen atoms takes place.

Reduction is the process in which either there is gain of electrons, oxidation number decreases, or gain of hydrogen atoms takes place.

Answer to Problem 15.41FU

Hydrogen is getting oxidized while oxygen is getting reduced in the chemical reaction.

Explanation of Solution

Given information:

The reaction between hydrogen gas and oxygen gas results in the formation of aqueous hydrogen peroxide.

The chemical reaction is given as:

  ${\text{H}}_{\text{2}}{\text{+O}}_{\text{2}}\underset{{\text{Al}}_{\text{2}}{\text{O}}_{\text{3}}}{\overset{\text{Pd/Au}}{\to }}{\text{H}}_{\text{2}}{\text{O}}_{\text{2}}$

Here, in the above reaction, the oxidation state of hydrogen is 0 on left hand side as it is present in elemental state. Similarly, oxidation state of oxygen is 0 on left hand side.

Now, calculate the oxidation state of oxygen in ${\text{H}}_{\text{2}}{\text{O}}_{\text{2}}$ .

First, oxidation state of hydrogen is assigned as +1. Let x be the oxidation state of oxygen and the compound is neutral. Thus,

  $\begin{array}{l}2(+1)+2x=0\\ 2+2x=0\\ x=-\frac{2}{2}=-1\end{array}$

Now, oxidation state of hydrogen increases from 0 to +1, thus, it is oxidized whereas oxidation state of oxygen is decreases from 0 to -1, thus it is reduced.

(b)

Interpretation Introduction

Interpretation:

The oxidizing agent in the given chemical reaction should be determined.

Concept Introduction:

The oxidizing agent can be defined as the substance that has ability to extract the electrons from the other substance in the redox reaction.

Answer to Problem 15.41FU

Oxygen is an oxidizing agent in the chemical reaction, since it is getting reduced.

Explanation of Solution

Given information:

The reaction between hydrogen gas and oxygen gas results in the formation of aqueous hydrogen peroxide.

The chemical reaction is given as:

  ${\text{H}}_{\text{2}}{\text{+O}}_{\text{2}}\underset{{\text{Al}}_{\text{2}}{\text{O}}_{\text{3}}}{\overset{\text{Pd/Au}}{\to }}{\text{H}}_{\text{2}}{\text{O}}_{\text{2}}$

Here, in the above reaction, the oxidation state of hydrogen is 0 on left hand side as it is present in elemental state. Similarly, oxidation state of oxygen is 0 on left hand side.

Now, calculate the oxidation state of oxygen in ${\text{H}}_{\text{2}}{\text{O}}_{\text{2}}$ .

First, oxidation state of hydrogen is assigned as +1. Let x be the oxidation state of oxygen and the compound is neutral. Thus,

  $\begin{array}{l}2(+1)+2x=0\\ 2+2x=0\\ x=-\frac{2}{2}=-1\end{array}$

Now, oxidation state of hydrogen increases from 0 to +1, thus, it is oxidized whereas oxidation state of oxygen is decreases from 0 to -1 by addition of electron, thus it is reduced.

Therefore, oxygen is an oxidizing agent as it is reduced.

(c)

Interpretation Introduction

Interpretation:

The reducing agent in the given chemical reaction should be determined.

Concept Introduction:

The reducing agent can be defined as the substances that have ability to donate the electrons to the other substance in the redox reaction.

Answer to Problem 15.41FU

Hydrogen is reducing agent in the chemical reaction, since it is getting oxidized.

Explanation of Solution

Given information:

The reaction between hydrogen gas and oxygen gas results in the formation of aqueous hydrogen peroxide.

The chemical reaction is given as:

  ${\text{H}}_{\text{2}}{\text{+O}}_{\text{2}}\underset{{\text{Al}}_{\text{2}}{\text{O}}_{\text{3}}}{\overset{\text{Pd/Au}}{\to }}{\text{H}}_{\text{2}}{\text{O}}_{\text{2}}$

Here, in the above reaction, the oxidation state of hydrogen is 0 on left hand side as it is present in elemental state. Similarly, oxidation state of oxygen is 0 on left hand side.

Now, calculate the oxidation state of oxygen in ${\text{H}}_{\text{2}}{\text{O}}_{\text{2}}$ .

First, oxidation state of hydrogen is assigned as +1. Let x be the oxidation state of oxygen and the compound is neutral. Thus,

  $\begin{array}{l}2(+1)+2x=0\\ 2+2x=0\\ x=-\frac{2}{2}=-1\end{array}$

Now, oxidation state of hydrogen increases from 0 to +1 by loss of electron, thus, it is oxidized whereas oxidation state of oxygen is decreases from 0 to -1, thus it is reduced.

Therefore, hydrogen is a reducing agent as it is oxidized.

(d)

Interpretation Introduction

Interpretation:

The balanced chemical equation for the given chemical reaction should be written.

Concept Introduction:

A balanced reaction is a reaction in which number of atoms and charges should be equal on both reactant as well as on product sides.

Answer to Problem 15.41FU

The balanced chemical equation is:

  ${\text{H}}_{\text{2}}{\text{+O}}_{\text{2}}\underset{{\text{Al}}_{\text{2}}{\text{O}}_{\text{3}}}{\overset{\text{Pd/Au}}{\to }}{\text{H}}_{\text{2}}{\text{O}}_{\text{2}}$

Explanation of Solution

Given information:

The reaction between hydrogen gas and oxygen gas results in the formation of aqueous hydrogen peroxide.

The chemical reaction is given as:

  ${\text{H}}_{\text{2}}{\text{+O}}_{\text{2}}\underset{{\text{Al}}_{\text{2}}{\text{O}}_{\text{3}}}{\overset{\text{Pd/Au}}{\to }}{\text{H}}_{\text{2}}{\text{O}}_{\text{2}}$

As this reaction doesn’t takes place by direct combination of hydrogen or oxygen, catalyst is used for occurrence of this reaction.

Here, number of hydrogen atoms is two on product side as well as on reactant side and number of oxygen atoms is two on product side as well as on reactant side.

Thus, reaction is balanced.