Chapter 7, Problem 51QAP

Interpretation Introduction

(a)

Interpretation:

Give two examples of single displacement and double displacement. How the two reactions are types of similar and how are they different.

Concept Introduction:

Displacement or Replacement reaction:

There are two types of Displacement or Replacement reactions which are follows:

1. Single Replacement or displacement reaction.
2. Double Replacement or displacement reaction.

Single Replacement reaction:

In Single Replacement or displacement one element or group of reactant is replaced by another element or group. For example the reaction between $\text{Z}\text{n}$ and $\text{H}\text{C}\text{l}$

$\text{Zn (}\text{s}\text{)+ 2 HCl }(aq)\to {\text{H}}_2(g)+{\text{ZnCl}}_{\text{2}}(aq)$

In the above reaction hydrogen is replaced by zinc metal.

Double Replacement or displacement reaction:

In Double Replacement or displacement reaction all element or group of reactants is replaced by another element or group. For example the reaction between $\text{B}\text{a}\text{C}{\text{l}}_2$ and $\text{N}{\text{a}}_2\text{S}{\text{O}}_4$ as follows:

$\text{B}\text{a}\text{C}{\text{l}}_2(aq)+\text{N}{\text{a}}_2\text{S}{\text{O}}_4(aq)\to 2\text{N}\text{a}\text{C}\text{l}(aq)+\text{B}\text{a}\text{S}{\text{O}}_4(s)$

In the reaction between $\text{B}\text{a}\text{C}{\text{l}}_2$ and $\text{N}{\text{a}}_2\text{S}{\text{O}}_4$ both replaced and sodium chloride, $\text{N}\text{a}\text{C}\text{l}$ and barium suplahte, $\text{B}\text{a}\text{S}{\text{O}}_4$ formed.

Answer to Problem 51QAP

Examples of Double Replacement or displacement reactions:

$\text{K}\text{C}\text{l}(aq)+\text{A}\text{g}\text{N}{\text{O}}_3(aq)\to \text{A}\text{g}\text{C}\text{l}(s)+\text{K}\text{N}{\text{O}}_3(aq)$

$\text{B}\text{a}\text{C}{\text{l}}_2(aq)+\text{N}{\text{a}}_2\text{S}{\text{O}}_4(aq)\to 2\text{N}\text{a}\text{C}\text{l}(aq)+\text{B}\text{a}\text{S}{\text{O}}_4(s)$

Examples of single Replacement or displacement reactions:

$\text{Zn (}\text{s}\text{)+ 2 HCl }(aq)\to {\text{H}}_2(g)+{\text{ZnCl}}_{\text{2}}(aq)$

$\text{F}\text{e}(s)+2\text{H}\text{C}\text{l}(aq)\to {\text{H}}_2(g)+\text{F}\text{e}\text{C}{\text{l}}_2(aq)$

In the above two reactions single displacement and double displacement reactions; displacement or replacement occurred by another group or element.

The double Replacement or displacement reaction is an example of precipitate reaction while single displacement not.

Explanation of Solution

Single Replacement reaction:

In Single Replacement or displacement one element or group of reactant is replaced by another element or group. For example the reaction between $\text{Z}\text{n}$ and $\text{H}\text{C}\text{l}$

$\text{Zn (}\text{s}\text{)+ 2 HCl }(aq)\to {\text{H}}_2(g)+{\text{ZnCl}}_{\text{2}}(aq)$

In the above reaction hydrogen is replaced by zinc metal.

Double Replacement or displacement reaction:

In Double Replacement or displacement reaction all element or group of reactants is replaced by another element or group. For example the reaction between $\text{B}\text{a}\text{C}{\text{l}}_2$ and $\text{N}{\text{a}}_2\text{S}{\text{O}}_4$ as follows:

$\text{B}\text{a}\text{C}{\text{l}}_2(aq)+\text{N}{\text{a}}_2\text{S}{\text{O}}_4(aq)\to 2\text{N}\text{a}\text{C}\text{l}(aq)+\text{B}\text{a}\text{S}{\text{O}}_4(s)$

In the reaction between $\text{B}\text{a}\text{C}{\text{l}}_2$ and $\text{N}{\text{a}}_2\text{S}{\text{O}}_4$ both replaced and sodium chloride, $\text{N}\text{a}\text{C}\text{l}$ and barium suplahte, $\text{B}\text{a}\text{S}{\text{O}}_4$ formed.

Examples of Double Replacement or displacement reactions:

$\text{K}\text{C}\text{l}(aq)+\text{A}\text{g}\text{N}{\text{O}}_3(aq)\to \text{A}\text{g}\text{C}\text{l}(s)+\text{K}\text{N}{\text{O}}_3(aq)$

$\text{B}\text{a}\text{C}{\text{l}}_2(aq)+\text{N}{\text{a}}_2\text{S}{\text{O}}_4(aq)\to 2\text{N}\text{a}\text{C}\text{l}(aq)+\text{B}\text{a}\text{S}{\text{O}}_4(s)$

Examples of single Replacement or displacement reactions:

$\text{Zn (}\text{s}\text{)+ 2 HCl }(aq)\to {\text{H}}_2(g)+{\text{ZnCl}}_{\text{2}}(aq)$

$\text{F}\text{e}(s)+2\text{H}\text{C}\text{l}(aq)\to {\text{H}}_2(g)+\text{F}\text{e}\text{C}{\text{l}}_2(aq)$

In the above two reactions single displacement and double displacement reactions; displacement or replacement occurred by another group or element.

The double Replacement or displacement reaction is an example of precipitate reaction while single displacement not.

Interpretation Introduction

(b)

Interpretation:

Give two examples of reactions in which water and gases are the driving forces.

Concept Introduction:

The most common driving forces which create product in chemical reactions are as follows:

1. Formation of a solid.
2. Formation of water.
3. Transfer of electrons.
4. Formation of gas.

Answer to Problem 51QAP

The formation of gas is an evidence of a chemical reaction because gas present as molecule from not in ion forms.

Examples $\text{Zn (}\text{s}\text{)+ 2 HCl }(aq)\to {\text{H}}_2(g)+{\text{ZnCl}}_{\text{2}}(aq)$

$\text{F}\text{e}(s)+2\text{H}\text{C}\text{l}(aq)\to {\text{H}}_2(g)+\text{F}\text{e}\text{C}{\text{l}}_2(aq)$

The formation of water is an evidence of a chemical reaction because water is present as molecule from not in ion forms.

Examples

$\text{N}\text{a}\text{O}\text{H}(aq)+\text{H}\text{C}\text{l}(aq)\to \text{N}\text{a}\text{C}\text{l}(aq)+{\text{H}}_2\text{O}(l)$

${\text{H}}_2{\text{O}}_2(aq)\to {\text{H}}_2\text{O}(l)+{\text{O}}_2(g)$.

Explanation of Solution

The formation of gas is an evidence of a chemical reaction because gas present as molecule from not in ion forms.

Examples:

$\text{Zn (}\text{s}\text{)+ 2 HCl }(aq)\to {\text{H}}_2(g)+{\text{ZnCl}}_{\text{2}}(aq)$

$\text{F}\text{e}(s)+2\text{H}\text{C}\text{l}(aq)\to {\text{H}}_2(g)+\text{F}\text{e}\text{C}{\text{l}}_2(aq)$

The formation of water is an evidence of a chemical reaction because water is present as molecule from not in ion forms.

Examples

$\text{N}\text{a}\text{O}\text{H}(aq)+\text{H}\text{C}\text{l}(aq)\to \text{N}\text{a}\text{C}\text{l}(aq)+{\text{H}}_2\text{O}(l)$

${\text{H}}_2{\text{O}}_2(aq)\to {\text{H}}_2\text{O}(l)+{\text{O}}_2(g)$.