Chapter 8, Problem 34A

a.

Interpretation Introduction

Interpretation: The category for the following reaction needs to be identified:

  ${\text{K}}_{\text{2}}{\text{SO}}_{\text{4}}{\text{(aq) + Ba(NO}}_{\text{3}}{\text{)}}_{\text{2}}\text{(aq) }\to {\text{ BaSO}}_{\text{4}}{\text{(s) + KNO}}_{\text{3}}\text{(aq)}$

Concept Introduction: A reaction in which there is a formation of an insoluble salt due to the mixing of solutions containing soluble salts is said to be precipitation reaction.

Answer to Problem 34A

Precipitation reaction.

Explanation of Solution

In the given reaction, aqueous solution of ${\text{K}}_{\text{2}}{\text{SO}}_{\text{4}}$ and ${\text{Ba(NO}}_{\text{3}}{\text{)}}_{\text{2}}$ reacts to form solid ${\text{BaSO}}_{\text{4}}$ and aqueous ${\text{KNO}}_{\text{3}}$ . Since, in the given reaction there is a formation of an insoluble salt, ${\text{BaSO}}_{\text{4}}$ by mixing solutions containing soluble salts, ${\text{K}}_{\text{2}}{\text{SO}}_{\text{4}}$ and ${\text{Ba(NO}}_{\text{3}}{\text{)}}_{\text{2}}$ so, the reaction is precipitation reaction.

b.

Interpretation Introduction

Interpretation: The category for the following reaction needs to be identified:

  $\text{HCl(aq) + Zn(s) }\to {\text{ H}}_2{\text{(g) + ZnCl}}_2\text{(aq)}$

Concept Introduction: A chemical reaction that involves the transfer of electron(s) between the species is said to be oxidation-reduction reaction. In this type of reaction, the oxidation number of atoms, molecule, or ion changes due to loss or addition of electron(s).

Answer to Problem 34A

Oxidation-reduction reaction.

Explanation of Solution

The oxidation state is defined as the charge(s) that an atom would have when electron(s) were transferred completely from a molecule or ion. (The element being oxidized is the one whose oxidation number increases in the reaction whereas the reduced element is the one whose oxidation number decreases in the reaction.)

The oxidation number of the involved elements in the given reaction is:

  $\begin{array}{l}\text{ HCl(aq) + Zn(s) }\to {\text{ H}}_2{\text{(g) + ZnCl}}_2\text{(aq)}\\ \text{oxidation state: +1 -1 0 0 +2 2(-1)}\end{array}$

In the given reaction, the oxidation state of hydrogen decreases from +1 to 0 and the oxidation state of zinc increases from 0 to +2. Since, hydrogen undergo reduction and zinc undergo oxidation so, the reaction is oxidation-reduction reaction.

c.

Interpretation Introduction

Interpretation: The category for the following reaction needs to be identified:

  ${\text{HCl(aq) + AgNO}}_3\text{(aq) }\to {\text{ HNO}}_3\text{(aq) + AgCl(s)}$

Concept Introduction: A reaction in which there is a formation of an insoluble salt due to the mixing of solutions containing soluble salts is said to be precipitation reaction.

Answer to Problem 34A

Precipitation reaction.

Explanation of Solution

In the given reaction, aqueous solution of $\text{HCl}$ and ${\text{AgNO}}_3$ reacts to form solid $\text{AgCl}$ and aqueous ${\text{HNO}}_3$ . Since, in the given reaction there is a formation of an insoluble salt, $\text{AgCl}$ by mixing solutions containing soluble salts, $\text{HCl}$ and ${\text{AgNO}}_3$ so, the reaction is precipitation reaction.

d.

Interpretation Introduction

Interpretation: The category for the following reaction needs to be identified:

  $\text{HCl(aq) + KOH(aq) }\to {\text{ H}}_2\text{O(l) + KCl(aq)}$

Concept Introduction: The reaction between a strong base and a strong acid result in the production of an ionic salt and water. The ionic salt is composed of cation from strong base and anion from strong acid. This type of reactions is said to be acid-base or neutralization reaction.

Answer to Problem 34A

Acid-base reaction.

Explanation of Solution

In the given reaction, $\text{HCl}$ acts as ab acid as it donates hydrogen ion, ${\text{H}}^{+}$ and $\text{KOH}$ acts as a base as it donates hydroxide ions, ${\text{OH}}^{-}$ . Since on reacting $\text{HCl}$ and $\text{KOH}$ it results in the formation of salt, $\text{KCl}$ and water, ${\text{H}}_2\text{O}$ so, it is an acid-base reaction.

e.

Interpretation Introduction

Interpretation: The category for the following reaction needs to be identified:

  ${\text{Zn(s) + CuSO}}_4\text{(aq) }\to {\text{ ZnSO}}_4\text{(aq) + Cu(s)}$

Concept Introduction: A chemical reaction that involves the transfer of electron(s) between the species is said to be oxidation-reduction reaction. In this type of reaction, the oxidation number of atoms, molecule, or ion changes due to loss or addition of electron(s).

Answer to Problem 34A

Oxidation-reduction reaction.

Explanation of Solution

The oxidation state is defined as the charge(s) that an atom would have when electron(s) were transferred completely from a molecule or ion. (The element being oxidized is the one whose oxidation number increases in the reaction whereas the reduced element is the one whose oxidation number decreases in the reaction.)

The oxidation number of the involved elements in the given reaction is:

  $\begin{array}{l}{\text{ Zn(s) + CuSO}}_4\text{(aq) }\to {\text{ ZnSO}}_4\text{(aq) + Cu(s)}\\ \text{oxidation state: 0 +2 +2 0 }\end{array}$

In the given reaction, the oxidation state of copper decreases from +2 to 0 and the oxidation state of zinc increases from 0 to +2. Since, copper undergo reduction and zinc undergo oxidation so, the reaction is oxidation-reduction reaction.

f.

Interpretation Introduction

Interpretation: The category for the following reaction needs to be identified:

  ${\text{NaH}}_{\text{2}}{\text{PO}}_{\text{4}}\text{(aq) + NaOH(aq) }\to {\text{ Na}}_{\text{3}}{\text{PO}}_{\text{4}}{\text{(aq) + H}}_{\text{2}}\text{O(l)}$

Concept Introduction: The reaction between a strong base and a strong acid result in the production of an ionic salt and water. The ionic salt is composed of cation from strong base and anion from strong acid. This type of reactions is said to be acid-base or neutralization reaction.

Answer to Problem 34A

Acid-base reaction.

Explanation of Solution

In the given reaction, ${\text{NaH}}_{\text{2}}{\text{PO}}_{\text{4}}$ acts as an acid as it donates hydrogen ion, ${\text{H}}^{+}$ and $\text{NaOH}$ acts as a base as it donates hydroxide ions, ${\text{OH}}^{-}$ . Since on reacting ${\text{NaH}}_{\text{2}}{\text{PO}}_{\text{4}}$ and $\text{NaOH}$ it results in the formation of salt, ${\text{Na}}_{\text{3}}{\text{PO}}_{\text{4}}$ and water, ${\text{H}}_2\text{O}$ so, it is an acid-base reaction.

g.

Interpretation Introduction

Interpretation: The category for the following reaction needs to be identified:

  ${\text{Ca(OH)}}_2{\text{(aq) + H}}_2{\text{SO}}_{\text{4}}\text{(aq) }\to {\text{ CaSO}}_{\text{4}}{\text{(s) + H}}_{\text{2}}\text{O(l)}$

Concept Introduction: The reaction between a strong base and a strong acid result in the production of an ionic salt and water. The ionic salt is composed of cation from strong base and anion from strong acid. This type of reactions is said to be acid-base or neutralization reaction.

Answer to Problem 34A

Acid-base reaction.

Explanation of Solution

In the given reaction, ${\text{H}}_2{\text{SO}}_{\text{4}}$ acts as an acid as it donates hydrogen ion, ${\text{H}}^{+}$ and ${\text{Ca(OH)}}_2$ acts as a base as it donates hydroxide ions, ${\text{OH}}^{-}$ . Since on reacting ${\text{H}}_2{\text{SO}}_{\text{4}}$ and ${\text{Ca(OH)}}_2$ it results in the formation of salt, ${\text{CaSO}}_{\text{4}}$ and water, ${\text{H}}_2\text{O}$ so, it is an acid-base reaction.

h.

Interpretation Introduction

Interpretation: The category for the following reaction needs to be identified:

  ${\text{ZnCl}}_2\text{(aq) + Mg(s) }\to {\text{ Zn(s) + MgCl}}_2\text{(aq)}$

Concept Introduction: A chemical reaction that involves the transfer of electron(s) between the species is said to be oxidation-reduction reaction. In this type of reaction, the oxidation number of atoms, molecule, or ion changes due to loss or addition of electron(s).

Answer to Problem 34A

Oxidation-reduction reaction.

Explanation of Solution

The oxidation state is defined as the charge(s) that an atom would have when electron(s) were transferred completely from a molecule or ion. (The element being oxidized is the one whose oxidation number increases in the reaction whereas the reduced element is the one whose oxidation number decreases in the reaction.)

The oxidation number of the involved elements in the given reaction is:

  $\begin{array}{l}{\text{ ZnCl}}_2\text{(aq) + Mg(s) }\to {\text{ Zn(s) + MgCl}}_2\text{(aq)}\\ \text{oxidation state: +2 0 0 +2}\end{array}$

In the given reaction, the oxidation state of zinc decreases from +2 to 0 and the oxidation state of magnesium increases from 0 to +2. Since, zinc undergo reduction and magnesium undergo oxidation so, the reaction is oxidation-reduction reaction.

i

Interpretation Introduction

Interpretation: The category for the following reaction needs to be identified:

  ${\text{BaCl}}_{\text{2}}{\text{(aq) +H}}_{\text{2}}{\text{SO}}_{\text{4}}\text{(aq) }\to {\text{ BaSO}}_{\text{4}}\text{(s) + HCl(aq)}$

Concept Introduction: A reaction in which there is a formation of an insoluble salt due to the mixing of solutions containing soluble salts is said to be precipitation reaction.

Answer to Problem 34A

Precipitation reaction.

Explanation of Solution

In the given reaction, aqueous solution of ${\text{BaCl}}_{\text{2}}$ and ${\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}$ reacts to form solid ${\text{BaSO}}_{\text{4}}$ and aqueous $\text{HCl}$ . Since, in the given reaction there is a formation of an insoluble salt, ${\text{BaSO}}_{\text{4}}$ by mixing solutions containing soluble salts, ${\text{BaCl}}_{\text{2}}$ and ${\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}$ so, the reaction is precipitation reaction.