Chapter 9, Problem 9.125QP

Classify the following reactions according to the types discussed in the chapter:

(a) Cl₂ + 2OH⁻ → Cl⁻ + ClO⁻ + H₂O

(b) Ca²⁺ + CO3²⁻ → CaCO₃

(c) NH₃ + H⁺ → NH4⁺

(d) 2CCl₄ + CrO₄²⁻ → 2COCl₂ + CrO₂Cl₂ + 2Cl⁻

(c) Ca + F₂ → CaF₂

(f) 2Li + H₂ → 2LiH

(g) Ba(NO₃)₂ + Na₂SO₄ → 2NaNO₃ + BaSO₄

(h) CuO + H₂ → Cu + H₂O

(i) Zn + 2HCl → ZnCl₂ + H₂

(j) 2FeCl₂ + Cl₂ → 2FeCl₃

Interpretation Introduction

Interpretation:

The given reaction has should be classified as redox reaction, acid –base, precipitation reaction and combination reaction.

Concept introduction:

Redox reaction:

• The oxidation number of a molecule is varied by involving in a reaction is known redox reaction.  The oxidation and reduction of chemical compounds takes place while they are involving in the reaction is called redox reaction.

Acid -Base reaction:

• The reaction between acid and base to produce a salt is called acid-base reaction.

Precipitation reaction:

• If precipitate is formed, when the two solutions are mixed together is called precipitation reaction.

Combination reaction:

• In the reaction, there is no change in oxidation numbers of atoms present in the reactants and products is and only the product is offered by the combination of reactants is called combination reaction.

Answer to Problem 9.125QP

It is a redox reaction

Explanation of Solution

• The oxidation and reduction of chemical compounds takes place while they are involving in the reaction is called redox reaction.

  ${\text{Cl}}_{\text{2}}{\text{+2OH}}^{\text{-}}\to {\text{Cl}}^{\text{-}}{\text{+ClO}}^{\text{-}}{\text{+H}}_{\text{2}}\text{O}$

• The chlorine is gained an electron to produce the ${\text{Cl}}^{\text{-}}$ ion.  Oxidation state of Cl is reduced from 0 to $-1.$ which can be termed as reduction reaction.  Besides it has bonded with a highly electronegative atom oxygen so that oxidation also has occurred.  Oxidation state of Cl is increased from 0 to $+1$ in $Cl{O}^{-}.$  Thus Cl is both oxidized and reduced.  Hence it is a redox reaction.

Interpretation Introduction

Interpretation:

The given reactions are should be classified as redox reaction, acid –base, precipitation reaction and combination reaction.

Concept introduction:

Redox reaction:

• The oxidation number of a molecule is varied by involving in a reaction is known redox reaction.  The oxidation and reduction of chemical compounds takes place while they are involving in the reaction is called redox reaction.

Acid -Base reaction:

• The reaction between acid and base to produce a salt is called acid-base reaction.

Precipitation reaction:

• If precipitate is formed, when the two solutions are mixed together is called precipitation reaction.

Combination reaction:

• In the reaction, there is no change in oxidation numbers of atoms present in the reactants and products is and only the product is offered by the combination of reactants is called combination reaction.

Answer to Problem 9.125QP

This is a precipitation reaction

Explanation of Solution

• If precipitate is formed, when the two solutions mixed together is called precipitation reaction.

  ${\text{Ca}}^{\text{2+}}{\text{+CO}}_{\text{3}}{}^{\text{2-}}\to {\text{CaCO}}_{\text{3}}\downarrow$

• The solutions of ${\text{Ca}}^{\text{2+}}$ and ${\text{CO}}_{\text{3}}{}^{\text{2-}}$ are mixed together to form a ${\text{CaCO}}_{\text{3}}$ precipitate so it is a precipitation reaction.

Interpretation Introduction

Interpretation:

The given reactions are should be classified as redox reaction, acid –base, precipitation reaction and combination reaction.

Concept introduction:

Redox reaction:

• The oxidation number of a molecule is varied by involving in a reaction is known redox reaction.  The oxidation and reduction of chemical compounds takes place while they are involving in the reaction is called redox reaction.

Acid -Base reaction:

• The reaction between acid and base to produce a salt is called acid-base reaction.

Precipitation reaction:

• If precipitate is formed, when the two solutions are mixed together is called precipitation reaction.

Combination reaction:

• In the reaction, there is no change in oxidation numbers of atoms present in the reactants and products is and only the product is offered by the combination of reactants is called combination reaction.

Answer to Problem 9.125QP

This is an acid-base reaction

Explanation of Solution

• The reaction between acid and base to produce a salt is called acid-base reaction.

  ${\text{NH}}_{\text{3}}{\text{+H}}^{\text{+}}\to {\text{NH}}_{\text{4}}{}^{\text{+}}$

• The acid is reacting with Ammonia base to give an Ammonium salt.  So, it is an acid-base reaction.

Interpretation Introduction

Interpretation:

The given reactions are should be classified as redox reaction, acid –base, precipitation reaction and combination reaction.

Concept introduction:

Redox reaction:

• The oxidation number of a molecule is varied by involving in a reaction is known redox reaction.  The oxidation and reduction of chemical compounds takes place while they are involving in the reaction is called redox reaction.

Acid -Base reaction:

• The reaction between acid and base to produce a salt is called acid-base reaction.

Precipitation reaction:

• If precipitate is formed, when the two solutions are mixed together is called precipitation reaction.

Combination reaction:

• In the reaction, there is no change in oxidation numbers of atoms present in the reactants and products is and only the product is offered by the combination of reactants is called combination reaction.

Answer to Problem 9.125QP

This is combination reaction

Explanation of Solution

• In the reaction, there is no change in oxidation numbers of atoms present in the reactants and products is and only the product is offered by the combination of reactants is called combination reaction.

  ${\text{2CCl}}_{\text{4}}{\text{+CrO}}_{\text{4}}{}^{\text{2-}}\to {\text{2COCl}}_{\text{2}}{\text{+CrO}}_{\text{2}}{\text{Cl}}_{\text{2}}{\text{+2Cl}}^{\text{-}}$

• In the above given reaction, there is no change in oxidation numbers of atoms present in the reactants and products is and only the product is offered by the combination of reactants so it is a combination reaction.

Interpretation Introduction

Interpretation:

The given reactions are should be classified as redox reaction, acid –base, precipitation reaction and combination reaction.

Concept introduction:

Redox reaction:

• The oxidation number of a molecule is varied by involving in a reaction is known redox reaction.  The oxidation and reduction of chemical compounds takes place while they are involving in the reaction is called redox reaction.

Acid -Base reaction:

• The reaction between acid and base to produce a salt is called acid-base reaction.

Precipitation reaction:

• If precipitate is formed, when the two solutions are mixed together is called precipitation reaction.

Combination reaction:

• In the reaction, there is no change in oxidation numbers of atoms present in the reactants and products is and only the product is offered by the combination of reactants is called combination reaction.

Answer to Problem 9.125QP

This is a redox reaction

Explanation of Solution

The type of given reaction

• The oxidation and reduction of chemical compounds takes place while they are involving in the reaction is called redox reaction.

  ${\text{Ca+F}}_{\text{2}}\to {\text{CaF}}_{\text{2}}$

• Oxidation number of F is changed from 0 to $-1$ in the reaction.  It indicates Fluorine is reduced.  Oxidation number of Ca is changed from 0 to $+2$ in the reaction.  It indicates Calcium is oxidized.  So it is a redox reaction.

Interpretation Introduction

Interpretation:

The given reactions are should be classified as redox reaction, acid –base, precipitation reaction and combination reaction.

Concept introduction:

Redox reaction:

• The oxidation number of a molecule is varied by involving in a reaction is known redox reaction.  The oxidation and reduction of chemical compounds takes place while they are involving in the reaction is called redox reaction.

Acid -Base reaction:

• The reaction between acid and base to produce a salt is called acid-base reaction.

Precipitation reaction:

• If precipitate is formed, when the two solutions are mixed together is called precipitation reaction.

Combination reaction:

• In the reaction, there is no change in oxidation numbers of atoms present in the reactants and products is and only the product is offered by the combination of reactants is called combination reaction.

Answer to Problem 9.125QP

This is a redox reaction

Explanation of Solution

The type of given reaction

• The oxidation and reduction of chemical compounds takes place while they are involving in the reaction is called redox reaction.

  ${\text{2Li+H}}_{\text{2}}\to \text{2LiH}$

• The Hydrogen is gained a one electron to produce the ${\text{H}}^{\text{-}}$ ion and Lithium lost one electron to produce ${\text{Li}}^{\text{+}}$ ion.  Thus both reduction and oxidation has occurred.  So it is a redox reaction.

Interpretation Introduction

Interpretation:

The given reactions are should be classified as redox reaction, acid –base, precipitation reaction and combination reaction.

Concept introduction:

Redox reaction:

• The oxidation number of a molecule is varied by involving in a reaction is known redox reaction.  The oxidation and reduction of chemical compounds takes place while they are involving in the reaction is called redox reaction.

Acid -Base reaction:

• The reaction between acid and base to produce a salt is called acid-base reaction.

Precipitation reaction:

• If precipitate is formed, when the two solutions are mixed together is called precipitation reaction.

Combination reaction:

• In the reaction, there is no change in oxidation numbers of atoms present in the reactants and products is and only the product is offered by the combination of reactants is called combination reaction.

Answer to Problem 9.125QP

This is a precipitation reaction

Explanation of Solution

• The oxidation and reduction of chemical compounds takes place while they are involving in the reaction is called redox reaction.

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

• The reaction between ${\text{Ba(NO}}_{\text{3}}{\text{)}}_{\text{2}}\text{and}{\text{Na}}_{\text{2}}{\text{SO}}_{\text{4}}$ is produce the ${\text{BaSO}}_{\text{4}}$ precipitate so it is a precipitation reaction.

Interpretation Introduction

Interpretation:

The given reactions are should be classified as redox reaction, acid –base, precipitation reaction and combination reaction.

Concept introduction:

Redox reaction:

• The oxidation number of a molecule is varied by involving in a reaction is known redox reaction.  The oxidation and reduction of chemical compounds takes place while they are involving in the reaction is called redox reaction.

Acid -Base reaction:

• The reaction between acid and base to produce a salt is called acid-base reaction.

Precipitation reaction:

• If precipitate is formed, when the two solutions are mixed together is called precipitation reaction.

Combination reaction:

• In the reaction, there is no change in oxidation numbers of atoms present in the reactants and products is and only the product is offered by the combination of reactants is called combination reaction.

Answer to Problem 9.125QP

This is a redox reaction

Explanation of Solution

• The oxidation and reduction of chemical compounds takes place while they are involving in the reaction is called redox reaction.

  ${\text{CuO+H}}_{\text{2}}\to {\text{Cu+H}}_{\text{2}}\text{O}$

• The oxidation state of copper is reduced to zero as it gained a two electron to produce the $\text{Cu}$ metal whereas oxidation state of Hydrogen is increased to $+1$ from zero.  This implies both reduction and oxidation has occurred.  So it is a redox reaction.

Interpretation Introduction

Interpretation:

The given reactions are should be classified as redox reaction, acid –base, precipitation reaction and combination reaction.

Concept introduction:

Redox reaction:

• The oxidation number of a molecule is varied by involving in a reaction is known redox reaction.  The oxidation and reduction of chemical compounds takes place while they are involving in the reaction is called redox reaction.

Acid -Base reaction:

• The reaction between acid and base to produce a salt is called acid-base reaction.

Precipitation reaction:

• If precipitate is formed, when the two solutions are mixed together is called precipitation reaction.

Combination reaction:

• In the reaction, there is no change in oxidation numbers of atoms present in the reactants and products is and only the product is offered by the combination of reactants is called combination reaction.

Answer to Problem 9.125QP

This is a redox reaction

Explanation of Solution

• The oxidation and reduction of chemical compounds takes place while they are involving in the reaction is called redox reaction.

  $\text{Zn+2HCl}\to {\text{ZnCl}}_{\text{2}}+{\text{H}}_{\text{2}}$

• The Zinc metal has lost two electron to produce the ${\text{ZnCl}}_{\text{2}}$ salt thus its oxidation state is increased to $+2$ from zero.  Oxidation state of Hydrogen is reduced to zero from $-1.$  This indicates both Cl and Zn are undergone change in oxidation number and oxidation and reduction reaction have occurred.  So, it is a redox reaction.

Interpretation Introduction

Interpretation:

The given reactions are should be classified as redox reaction, acid –base, precipitation reaction and combination reaction.

Concept introduction:

Redox reaction:

• The oxidation number of a molecule is varied by involving in a reaction is known redox reaction.  The oxidation and reduction of chemical compounds takes place while they are involving in the reaction is called redox reaction.

Acid -Base reaction:

• The reaction between acid and base to produce a salt is called acid-base reaction.

Precipitation reaction:

• If precipitate is formed, when the two solutions are mixed together is called precipitation reaction.

Combination reaction:

• In the reaction, there is no change in oxidation numbers of atoms present in the reactants and products is and only the product is offered by the combination of reactants is called combination reaction.

Answer to Problem 9.125QP

This is a redox reaction

Explanation of Solution

The type of given reaction

• The oxidation and reduction of chemical compounds takes place while they are involving in the reaction is called redox reaction.

  ${\text{2FeCl}}_{\text{2}}{\text{+Cl}}_{\text{2}}\to {\text{2FeCl}}_{\text{3}}$

• The iron ${\text{Fe}}^{\text{2}}{}^{\text{+ }}$ is lost one electron to produce the ${\text{FeCl}}_{\text{3}}$ that oxidation number of Fe is increased to $+3$ from $+2.$  oxidation number of Cl is also decreased to $-1$ from zero.  Thus both oxidation and reduction has occurred.
• So, it is a redox reaction.