Chapter 9, Problem 81P

Write a balanced equation for each reaction.
a. $\text{HBr}(aq)\text{ + KOH}(aq)\to$
b. ${\text{HNO}}_3(aq){\text{ + Ca(OH)}}_2(aq)\to$
c. $\text{HCI}(aq){\text{ + NaHCO}}_3(aq)\to$
d. ${\text{H}}_2{\text{SO}}_4(aq){\text{ + Mg(OH)}}_2(aq)\to$

Interpretation Introduction

(a)

Interpretation:

The balanced chemical equation of acid-base reaction between the aqueous solution of $\text{HBr}$ and $\text{KOH}$ needs to be determined.

Concept Introduction:

A substance is said to be acidic if it can give hydrogen ions ( ${\text{H}}^{\text{+}}$ ) whereas a base is a substance that can give ${\text{OH}}^{\text{-}}$ ion. This theory of acid and base is called the Arrhenius theory of acid and base.

Another theory that is purposed by Bronsted and Lowery is called Bronsted-Lowry acid-base theory. It states that acid can give ${\text{H}}^{\text{+}}$ ions whereas a base can accept the ${\text{H}}^{\text{+}}$ ion in its solution. Hence this theory is entirely based on the presence of ${\text{H}}^{\text{+}}$ ion in the given substance. It purposed the concept of conjugated acid-base pair. A Bronsted acid gives ${\text{H}}^{\text{+}}$ ion to form conjugated base whereas a Bronsted base accepts ${\text{H}}^{\text{+}}$ ion to form its conjugated acid.

  $\begin{array}{l}{\text{ HA + H}}_{\text{2}}\text{O }\underset{}{\to }{\text{ A}}^{\text{-}}{\text{ + H}}_{\text{3}}{\text{O}}^{\text{+}}\\ \text{Bronsted + Bronsted Conjugated Conjugated}\\ \text{ Acid base base acid}\end{array}$

Overall the reaction of acid and base forms salt and water as the product. This reaction is called a neutralization reaction.

Answer to Problem 81P

  $\begin{array}{l}{\text{HBr}}_{\text{(aq) }}{\text{+ KOH}}_{\text{(aq)}}\underset{}{\to }{\text{ KBr}}_{\text{(aq) }}{\text{ + H}}_{\text{2}}{\text{O}}_{\text{(l)}}\\ \text{ Acid + Base Salt + Water }\end{array}$

Explanation of Solution

Hydrobromic acid $\text{HBr}$ is soluble in water. Here $\text{HBr}$ acts as an acid as it gives ${\text{H}}^{\text{+}}$ ion and forms ${\text{Br}}^{\text{-}}$ ion. Potassium hydroxide $\text{KOH}$ is soluble in water. It acts as a base as it gives ${\text{OH}}^{\text{-}}$ ion and forms ${\text{K}}^{\text{+ }}$ ion. The ${\text{H}}^{\text{+}}$ ion from $\text{HBr}$ must be accepted by ${\text{OH}}^{\text{-}}$ ion from $\text{KOH}$ which results in the formation of ${\text{H}}_{\text{2}}\text{O}$ . Hence in the given reaction $\text{HBr}$ is an acid and $\text{KOH}$ is a base. The reaction of acid and base forms salt and water as the product. This reaction is called a neutralization reaction. The complete balance acid-base equation of $\text{HBr}$ with $\text{KOH}$ must be written as:

  $\begin{array}{l}{\text{HBr}}_{\text{(aq) }}{\text{+ KOH}}_{\text{(aq)}}\underset{}{\to }{\text{ KBr}}_{\text{(aq) }}{\text{ + H}}_{\text{2}}{\text{O}}_{\text{(l)}}\\ \text{ Acid + Base Salt + Water }\end{array}$

Interpretation Introduction

(b)

Interpretation:

The balanced chemical equation of acid-base reaction between the aqueous solution of ${\text{HNO}}_{\text{3}}$ and ${\text{Ca(OH)}}_{\text{2}}$ needs to be determined.

Concept Introduction:

A substance is said to be acidic if it can give hydrogen ions ( ${\text{H}}^{\text{+}}$ ) whereas a base is a substance that can give ${\text{OH}}^{\text{-}}$ ion. This theory of acid and base is called the Arrhenius theory of acid and base.

Another theory that is purposed by Bronsted and Lowery is called Bronsted-Lowry acid-base theory. It states that acid can give ${\text{H}}^{\text{+}}$ ions whereas a base can accept the ${\text{H}}^{\text{+}}$ ion in its solution. Hence this theory is entirely based on the presence of ${\text{H}}^{\text{+}}$ ion in the given substance. It purposed the concept of conjugated acid-base pair. A Bronsted acid gives ${\text{H}}^{\text{+}}$ ion to form conjugated base whereas a Bronsted base accepts ${\text{H}}^{\text{+}}$ ion to form its conjugated acid.

  $\begin{array}{l}{\text{ HA + H}}_{\text{2}}\text{O }\underset{}{\to }{\text{ A}}^{\text{-}}{\text{ + H}}_{\text{3}}{\text{O}}^{\text{+}}\\ \text{Bronsted + Bronsted Conjugated Conjugated}\\ \text{ Acid base base acid}\end{array}$

Overall the reaction of acid and base forms salt and water as the product. This reaction is called a neutralization reaction.

Answer to Problem 81P

  $\begin{array}{l}{\text{2 HNO}}_{\text{3}}{}_{\text{(aq) }}{\text{+ Ca(OH)}}_{\text{2}}{}_{\text{(aq)}}\underset{}{\to }{\text{ Ca(NO}}_{\text{3}}{\text{)}}_{\text{2}}{}_{\text{(aq) }}{\text{ + 2 H}}_{\text{2}}{\text{O}}_{\text{(l)}}\\ \text{ Acid + Base Salt + Water }\end{array}$

Explanation of Solution

Nitric acid ${\text{HNO}}_{\text{3}}$ is soluble in water. Here ${\text{HNO}}_{\text{3}}$ acts as an acid as it gives ${\text{H}}^{\text{+}}$ ion and forms ${\text{NO}}_{\text{3}}{}^{-}$ ion. Calcium hydroxide ${\text{Ca(OH)}}_{\text{2}}$ is also soluble in water and acts as a base as it gives ${\text{OH}}^{\text{-}}$ ion and forms ${\text{Ca}}^{\text{2+ }}$ ion. The ${\text{H}}^{\text{+}}$ ion from ${\text{HNO}}_{\text{3}}$ must be accepted by ${\text{OH}}^{\text{-}}$ ion from ${\text{Ca(OH)}}_{\text{2}}$ which results in the formation of ${\text{H}}_{\text{2}}\text{O}$ . Hence in the given reaction ${\text{HNO}}_{\text{3}}$ is an acid and ${\text{Ca(OH)}}_{\text{2}}$ is a base. The reaction of acid and base forms salt and water as the product. This reaction is called a neutralization reaction. The complete balance acid-base equation of ${\text{HNO}}_{\text{3}}$ with ${\text{Ca(OH)}}_{\text{2}}$ must be written as:

  $\begin{array}{l}{\text{2 HNO}}_{\text{3}}{}_{\text{(aq) }}{\text{+ Ca(OH)}}_{\text{2}}{}_{\text{(aq)}}\underset{}{\to }{\text{ Ca(NO}}_{\text{3}}{\text{)}}_{\text{2}}{}_{\text{(aq) }}{\text{ + 2 H}}_{\text{2}}{\text{O}}_{\text{(l)}}\\ \text{ Acid + Base Salt + Water }\end{array}$

Interpretation Introduction

(c)

Interpretation:

The balanced chemical equation of acid-base reaction between the aqueous solution of $\text{HCl}$ and ${\text{NaHCO}}_{\text{3}}$ needs to be determined.

Concept Introduction:

A substance is said to be acidic if it can give hydrogen ions ( ${\text{H}}^{\text{+}}$ ) whereas a base is said to be a substance that can give ${\text{OH}}^{\text{-}}$ ion. This theory of acid and base is called the Arrhenius theory of acid and base.

Another theory that is purposed by Bronsted and Lowery is called Bronsted-Lowry acid-base theory. It states that acid can give ${\text{H}}^{\text{+}}$ ions whereas a base can accept the ${\text{H}}^{\text{+}}$ ion in its solution. Hence this theory is entirely based on the presence of ${\text{H}}^{\text{+}}$ ion in the given substance. It purposed the concept of conjugated acid-base pair. A Bronsted acid gives ${\text{H}}^{\text{+}}$ ion to form conjugated base whereas a Bronsted base accepts ${\text{H}}^{\text{+}}$ ion to form its conjugated acid.

  $\begin{array}{l}{\text{ HA + H}}_{\text{2}}\text{O }\underset{}{\to }{\text{ A}}^{\text{-}}{\text{ + H}}_{\text{3}}{\text{O}}^{\text{+}}\\ \text{Bronsted + Bronsted Conjugated Conjugated}\\ \text{ Acid base base acid}\end{array}$

Overall the reaction of acid and base forms salt and water as the product. This reaction is called a neutralization reaction.

Answer to Problem 81P

  $\begin{array}{l}{\text{HCl}}_{\text{(aq) }}{\text{+ NaHCO}}_{\text{3}}{}_{\text{(aq)}}\underset{}{\to }{\text{ NaCl}}_{\text{(aq) }}{\text{+ H}}_{\text{2}}{\text{O}}_{\text{(l)}}{\text{ + CO}}_{\text{2(g)}}\\ \text{Acid + Base Salt Water Carbon dioxide}\end{array}$

Explanation of Solution

Hydrochloric acid $\text{HCl}$ is soluble in water. Here $\text{HCl}$ acts as an acid as it gives ${\text{H}}^{\text{+}}$ ion and forms ${\text{Cl}}^{-}$ ion. Sodium hydrogen carbonate ${\text{NaHCO}}_{\text{3}}$ is also soluble in water and acts as a base. The ${\text{H}}^{\text{+}}$ ion from $\text{HCl}$ must be accepted by ${\text{NaHCO}}_{\text{3}}$ which results in the formation of ${\text{H}}_{\text{2}}\text{O}$ . Hence in the given reaction $\text{HCl}$ is an acid and ${\text{NaHCO}}_{\text{3}}$ is a base. The reaction of $\text{HCl}$ with ${\text{NaHCO}}_{\text{3}}$ forms $\text{NaCl}$ as salt and ${\text{H}}_{\text{2}}{\text{CO}}_{\text{3}}$ . Since ${\text{H}}_{\text{2}}{\text{CO}}_{\text{3}}$ is unstable so it readily decomposes to ${\text{H}}_{\text{2}}\text{O}$ and ${\text{CO}}_{\text{2(g)}}$ .Thus, the complete balance acid-base equation of $\text{HCl}$ with ${\text{NaHCO}}_{\text{3}}$ must be written as:

  $\begin{array}{l}{\text{HCl}}_{\text{(aq) }}{\text{+ NaHCO}}_{\text{3}}{}_{\text{(aq)}}\underset{}{\to }{\text{ NaCl}}_{\text{(aq) }}{\text{+ H}}_{\text{2}}{\text{O}}_{\text{(l)}}{\text{ + CO}}_{\text{2(g)}}\\ \text{Acid + Base Salt Water Carbon dioxide}\end{array}$

Interpretation Introduction

(d)

Interpretation:

The balanced chemical equation of acid-base reaction between the aqueous solution of ${\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}$ and ${\text{Mg(OH)}}_{\text{2}}$ needs to be determined.

Concept Introduction:

A substance is said to be acidic if it can give hydrogen ions ( ${\text{H}}^{\text{+}}$ ) whereas a base is said to be a substance that can give ${\text{OH}}^{\text{-}}$ ion. This theory of acid and base is called the Arrhenius theory of acid and base.

Another theory that is purposed by Bronsted and Lowery is called Bronsted-Lowry acid-base theory. It states that acid can give ${\text{H}}^{\text{+}}$ ions whereas a base can accept the ${\text{H}}^{\text{+}}$ ion in its solution. Hence this theory is entirely based on the presence of ${\text{H}}^{\text{+}}$ ion in the given substance. It purposed the concept of conjugated acid-base pair. A Bronsted acid gives ${\text{H}}^{\text{+}}$ ion to form conjugated base whereas a Bronsted base accepts ${\text{H}}^{\text{+}}$ ion to form its conjugated acid.

  $\begin{array}{l}{\text{ HA + H}}_{\text{2}}\text{O }\underset{}{\to }{\text{ A}}^{\text{-}}{\text{ + H}}_{\text{3}}{\text{O}}^{\text{+}}\\ \text{Bronsted + Bronsted Conjugated Conjugated}\\ \text{ Acid base base acid}\end{array}$

Overall the reaction of acid and base forms salt and water as the product. This reaction is called a neutralization reaction.

Answer to Problem 81P

  $\begin{array}{l}{\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}{}_{\text{(aq) }}{\text{+ Mg(OH)}}_{\text{2}}{}_{\text{(aq)}}\underset{}{\to }{\text{ MgSO}}_4{}_{\text{(aq) }}{\text{+ 2 H}}_{\text{2}}{\text{O}}_{\text{(l)}}\\ \text{ Acid + Base Salt Water }\end{array}$

Explanation of Solution

Sulfuric acid ${\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}$ is soluble in water. Here ${\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}$ acts as an acid as it gives ${\text{H}}^{\text{+}}$ ion and forms ${\text{SO}}_{\text{4}}{}^{2-}$ ion. Calcium hydroxide ${\text{Mg(OH)}}_{\text{2}}$ is also soluble in water and acts as a base as it gives ${\text{OH}}^{\text{-}}$ ion and forms ${\text{Mg}}^{\text{2+ }}$ ion. The ${\text{H}}^{\text{+}}$ ion from ${\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}$ must be accepted by ${\text{OH}}^{\text{-}}$ ion from ${\text{Mg(OH)}}_{\text{2}}$ which results in the formation of ${\text{H}}_{\text{2}}\text{O}$ . Hence in the given reaction ${\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}$ is an acid and ${\text{Mg(OH)}}_{\text{2}}$ is a base. The reaction of acid and base forms salt and water as the product. This reaction is called a neutralization reaction. The complete balance acid-base equation of ${\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}$ with ${\text{Mg(OH)}}_{\text{2}}$ must be written as:

  $\begin{array}{l}{\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}{}_{\text{(aq) }}{\text{+ Mg(OH)}}_{\text{2}}{}_{\text{(aq)}}\underset{}{\to }{\text{ MgSO}}_4{}_{\text{(aq) }}{\text{+ 2 H}}_{\text{2}}{\text{O}}_{\text{(l)}}\\ \text{ Acid + Base Salt Water }\end{array}$