Chapter 15, Problem 43UTC

(a)

Interpretation Introduction

Interpretation:

The loss of electrons needs to be classified as oxidation or reduction.

Concept Introduction :

In a redox reaction both oxidation and reduction take place simultaneously. Oxidation takes place by loss of electrons and reduction takes place by gain of electrons. The oxidation state of a species increases on oxidation and decreases on reduction. In a reaction, one of the reactants get oxidized and 1 gets reduced, this is known as a redox reaction.

Answer to Problem 43UTC

Oxidation reaction.

Explanation of Solution

When electrons are lost in a chemical reaction, the type of reaction is said to be an oxidation reaction. In this reaction, oxidation state of the species increases. The oxidation reaction is shown as follows:

  $\text{A}\to {\text{A}}^{+}+e^{-}$

Here, species A get oxidized to ${\text{A}}^{+}$ by loss of 1 electron.

(b)

Interpretation Introduction

Interpretation:

The reaction of an oxidizing agent needs to be classified as oxidation or reduction.

Concept Introduction :

In a redox reaction both oxidation and reduction take place simultaneously. Oxidation takes place by loss of electrons and reduction takes place by gain of electrons. The oxidation state of a species increases on oxidation and decreases on reduction. When in reaction 1, one of the reactants get oxidized and 1 gets reduced, this is known as a redox reaction. The species that oxidizes others and itself gets reduced is known as an oxidizing agent.

Answer to Problem 43UTC

Reduction reaction.

Explanation of Solution

An oxidizing agent is the chemical species which itself gain electron/s and oxidizes other species. Therefore, the reaction of an oxidizing agent is a reduction reaction.

For example:

  $\text{A}+{\text{B}}^{+}\to {\text{A}}^{+}+\text{B}$

Here, ${\text{B}}^{+}$ is an oxidizing agent as it oxidizes A to ${\text{A}}^{+}$ and itself gets reduced to B.

(c)

Interpretation Introduction

Interpretation:

The given reaction needs to be classified as oxidation or reduction:

  ${\text{O}}_{\text{2}}\left(g\right)\to {\text{OH}}^{-}\left(aq\right)$

Concept Introduction :

In a redox reaction both oxidation and reduction take place simultaneously. Oxidation takes place by loss of electrons and reduction takes place by gain of electrons. The oxidation state of a species increases on oxidation and decreases on reduction. In a reaction, oneof the reactants get oxidized and one gets reduced, this is known as a redox reaction. The species that oxidizes others and itself gets reduced is known as an oxidizing agent.

Answer to Problem 43UTC

Reduction reaction.

Explanation of Solution

The given reaction is as follows:

  ${\text{O}}_{\text{2}}\left(g\right)\to {\text{OH}}^{-}\left(aq\right)$

The oxidation state of molecular oxygen is zero. It gets reduced to -2 in ${\text{OH}}^{-}$ thus, oxygen is getting reduced.

Therefore, the above reaction is a reduction reaction.

(d)

Interpretation Introduction

Interpretation:

The given reaction needs to be classified as oxidation or reduction:

  ${\text{Br}}_{\text{2}}\left(l\right)\to 2{\text{Br}}^{-}\left(aq\right)$

Concept Introduction :

In a redox reaction both oxidation and reduction take place simultaneously. Oxidation takes place by loss of electrons and reduction takes place by gain of electrons. The oxidation state of a species increases on oxidation and decreases on reduction. In a reaction, one of the reactants get oxidized and 1 gets reduced, this is known as a redox reaction. The species that oxidizes others and itself gets reduced is known as an oxidizing agent.

Answer to Problem 43UTC

Reduction reaction.

Explanation of Solution

The given reaction is as follows:

  ${\text{Br}}_{\text{2}}\left(l\right)\to 2{\text{Br}}^{-}\left(aq\right)$

Here, in the molecular bromine or Br₂, the oxidation state of bromine is 0.

Now, in Br^-, since, it gets reduced to -1, the bromine undergoes reduction. This takes place by gaining 2 electrons as there are 2 Br atoms in 1 Br₂ molecule.

Therefore, the given reaction is reduction.

(e)

Interpretation Introduction

Interpretation:

The given reaction needs to be classified as oxidation or reduction:

  ${\text{Sn}}^{2+}\left(aq\right)\to {\text{Sn}}^{4+}\left(aq\right)$

Concept Introduction :

In a redox reaction both oxidation and reduction take place simultaneously. Oxidation takes place by loss of electrons and reduction takes place by gain of electrons. The oxidation state of a species increases on oxidation and decreases on reduction. In a reaction, one of the reactants get oxidized and one gets reduced, this is known as a redox reaction. The species that oxidizes others and itself gets reduced is known as an oxidizing agent.

Answer to Problem 43UTC

Oxidation reaction.

Explanation of Solution

In the given reaction is as follows:

  ${\text{Sn}}^{2+}\left(aq\right)\to {\text{Sn}}^{4+}\left(aq\right)$

The oxidation state of ‘Sn’ changes from +2 to +4. This means that Sn²+ loses2 electrons to form Sn⁴⁺. The oxidation state of an ion increases due to loss of electron/s thus, the given reaction is an oxidation reaction.