Chapter U5.18, Problem 5E

(a)

Interpretation Introduction

Interpretation:The chemical equation of any reaction that occur in exercise 3 and 4 needs to be written.

Concept Introduction : A chemical reaction is a symbolic representation of how reactants reacts in presence of adequate amount of temperature and reaction medium to generate a product.

Answer to Problem 5E

The chemical equation for the reaction in exercise 2 is,

  $\text{3Zn}\left(s\right)\text{+}\text{2Fe}{\left({\text{NO}}_{\text{3}}\right)}_{\text{3}}\to \text{3Zn}{\left({\text{NO}}_{\text{3}}\right)}_2+2\text{Fe}\left(s\right)$

Explanation of Solution

To write the chemical equation for the reaction in exercise 2, “if iron nitrate were combined with solid zinc, zinc nitrate will be generated” we must know the formula of the reactants and the products.

Chemical formula of iron nitrate is $\text{Fe}{\left({\text{NO}}_{\text{3}}\right)}_{\text{3}}$ , Zinc is Zn and Zinc nitrate is $\text{Zn}{\left({\text{NO}}_{\text{3}}\right)}_{\text{3}}$

Therefore, the chemical equation for the reaction is,

  $\text{3Zn}\left(s\right)\text{+}\text{2Fe}{\left({\text{NO}}_{\text{3}}\right)}_{\text{3}}\to \text{3Zn}{\left({\text{NO}}_{\text{3}}\right)}_2+2\text{Fe}\left(s\right)$

(b)

Interpretation Introduction

Interpretation:The net ionic equation for the reaction needs to be written.

Concept Introduction : A chemical reaction is a symbolic representation of how reactants react in presence of adequate amount of temperature and reaction medium to generate a product.

An ionic reaction is a symbolic representation of how ions reacts in a chemical reaction.

Answer to Problem 5E

The net ionic equation for the reaction is,

  ${\text{2Fe}}^{3+}\left(aq\right)\text{+}\text{3Zn}\left(s\right)\to {\text{3Zn}}^{2+}\left(aq\right)+2\text{Fe}\left(s\right)$

Explanation of Solution

The net ionic equation for the reaction

  $\text{3Zn}\left(s\right)\text{+}\text{2Fe}{\left({\text{NO}}_{\text{3}}\right)}_{\text{3}}\to \text{3Zn}{\left({\text{NO}}_{\text{3}}\right)}_2+2\text{Fe}\left(s\right)$ is,

  ${\text{2Fe}}^{3+}\left(aq\right)\text{+}\text{3Zn}\left(s\right)\to {\text{3Zn}}^{2+}\left(aq\right)+2\text{Fe}\left(s\right)$

Here, ${\text{Fe}}^{3+}$ undergoes reaction with Zn and generates ${\text{Zn}}^{2+}$ and Fe

(c)

Interpretation Introduction

Interpretation: The most active metal needs to be identified.

Concept Introduction : The reactivity series of metal in the order of increasing reactivity is,

Gold < Silver < Mercury < Bismuth < Antimony < Hydrogen < Lead < Tin < Nickel < Cobalt < Cadmium < Iron < Chromium < Zinc < Manganese < Aluminium < Calcium < Strontium < Barium < Lithium < Sodium < Potassium

Answer to Problem 5E

Zn is more active than Fe in the reaction,

  ${\text{2Fe}}^{3+}\left(aq\right)\text{+}\text{3Zn}\left(s\right)\to {\text{3Zn}}^{2+}\left(aq\right)+2\text{Fe}\left(s\right)$

Explanation of Solution

The activity series of metal in the order of increasing reactivity is,

Gold < Silver < Mercury < Bismuth < Antimony < Hydrogen < Lead < Tin < Nickel < Cobalt < Cadmium < Iron < Chromium < Zinc < Manganese < Aluminium < Calcium < Strontium < Barium < Lithium < Sodium < Potassium

This reactivity series implies that a metal with high reactivity can displace a metal with a low reactivity.

From the above series, we can conclude that Zn is most active in the reaction,

  ${\text{2Fe}}^{3+}\left(aq\right)\text{+}\text{3Zn}\left(s\right)\to {\text{3Zn}}^{2+}\left(aq\right)+2\text{Fe}\left(s\right)$

(d)

Interpretation Introduction

Interpretation: The oxidized and reduced metal needs to be determined.

Concept Introduction:The activity series of metal in the order of increasing reactivity is,

Gold < Silver < Mercury < Bismuth < Antimony < Hydrogen < Lead < Tin < Nickel < Cobalt < Cadmium < Iron < Chromium < Zinc < Manganese < Aluminium < Calcium < Strontium < Barium < Lithium < Sodium < Potassium

Answer to Problem 5E

Zn is oxidized and iron is reduced in the reaction,

  ${\text{2Fe}}^{3+}\left(aq\right)\text{+}\text{3Zn}\left(s\right)\to {\text{3Zn}}^{2+}\left(aq\right)+2\text{Fe}\left(s\right)$

Explanation of Solution

In the reaction,

  ${\text{2Fe}}^{3+}\left(aq\right)\text{+}\text{3Zn}\left(s\right)\to {\text{3Zn}}^{2+}\left(aq\right)+2\text{Fe}\left(s\right)$

Zinc is more active than Fe according to the following activity series,

Gold < Silver < Mercury < Bismuth < Antimony < Hydrogen < Lead < Tin < Nickel < Cobalt < Cadmium < Iron < Chromium < Zinc < Manganese < Aluminium < Calcium < Strontium < Barium < Lithium < Sodium < Potassium

Therefore, in the reaction Zn donates electrons and ${\text{Fe}}^{3+}$ accepts electrons. Therefore, we can conclude that Zn is oxidized and iron is reduced.