Chapter 8, Problem 8I.3E

(a)

Interpretation Introduction

Interpretation:

The balanced chemical equation for the thermal decomposition of potassium chlorate without catalyst has to be given.

Answer to Problem 8I.3E

The balance chemical equation is,

  ${\text{4KClO}}_{\text{3(l)}}\stackrel{\Delta }{\to }{\text{3KClO}}_{\text{4}}{}_{\left(\text{s}\right)}{\text{+KCl}}_{\left(\text{s}\right)}$

Explanation of Solution

On thermal decomposition, potassium chlorate decomposes into potassium perchlorate and potassium chloride.

The balanced chemical equation is,

  ${\text{4KClO}}_{\text{3(l)}}\stackrel{\Delta }{\to }{\text{3KClO}}_{\text{4}}{}_{\left(\text{s}\right)}{\text{+KCl}}_{\left(\text{s}\right)}$

(b)

Interpretation Introduction

Interpretation:

The balanced chemical equation for the reaction of bromine with water has to be given.

Answer to Problem 8I.3E

The balanced chemical equation is,

  ${\text{Br}}_{\text{2}\left(\text{l}\right)}{\text{+H}}_{\text{2}}{\text{O}}_{\left(\text{l}\right)}\stackrel{}{\to }{\text{HBrO}}_{\left(\text{aq}\right)}{\text{+HBr}}_{\left(\text{aq}\right)}$

Explanation of Solution

Bromine reacts with water to give hypobromous acid and hydrogen bromide.

The balanced chemical equation is,

  ${\text{Br}}_{\text{2}\left(\text{l}\right)}{\text{+H}}_{\text{2}}{\text{O}}_{\left(\text{l}\right)}\stackrel{}{\to }{\text{HBrO}}_{\left(\text{aq}\right)}{\text{+HBr}}_{\left(\text{aq}\right)}$

(c)

Interpretation Introduction

Interpretation:

The balanced chemical equation for the reaction between sodium chloride and concentrated sulfuric acid has to be given.

Answer to Problem 8I.3E

The balanced chemical equation is,

  ${\text{NaCl}}_{\left(\text{s}\right)}{\text{+H}}_{\text{2}}{\text{SO}}_{\text{4}\left(\text{aq}\right)}\stackrel{}{\to }{\text{NaHSO}}_{\text{4}\left(\text{aq}\right)}{\text{+HCl}}_{\left(\text{aq}\right)}$

Explanation of Solution

Sodium chloride reacts with concentrated sulfuric acid to give sodium hydrogen sulfate and hydrochloric acid.

The balanced chemical equation is,

  ${\text{NaCl}}_{\left(\text{s}\right)}{\text{+H}}_{\text{2}}{\text{SO}}_{\text{4}\left(\text{aq}\right)}\stackrel{}{\to }{\text{NaHSO}}_{\text{4}\left(\text{aq}\right)}{\text{+HCl}}_{\left(\text{aq}\right)}$

(d)

Interpretation Introduction

Interpretation:

The reactions has to identified as Bronsted acid-base or Lewis acid-base or redox reaction.

Concept Introduction:

Bronsted acid-base reaction:

An acid-base reaction according to Bronsted-Lowry definition is a transfer of a proton from one molecule or ion to another.

Lewis acid-base reaction:

A Lewis acid-base reaction is a chemical reaction that forms at least one covalent bond between an electron pair donor (Lewis-base) and an electron pair acceptor (Lewis acid).

The general form of Lewis acid-base reaction is,

  ${\text{A}}^{\text{+}}{\text{+B}}^{\text{-}}\stackrel{}{\to }\text{A-B}$

Redox reaction:

An oxidation-reduction (redox) reaction is a type of chemical reaction that involves a transfer of electrons between two species.  An oxidation-reduction reaction is any chemical reaction in which the oxidation number of a molecule, atom, or ion changes by gaining or losing an electron.

Answer to Problem 8I.3E

The reactions (a) and (b) are redox reactions whereas reaction (c) is acid-base reaction.

Explanation of Solution

The reaction (a) is,

  ${\text{4KClO}}_{\text{3(l)}}\stackrel{\Delta }{\to }{\text{3KClO}}_{\text{4}}{}_{\left(\text{s}\right)}{\text{+KCl}}_{\left(\text{s}\right)}$

In this reaction, the oxidation number of potassium gets reduced thus, it is a redox reaction.

The reaction (b) is,

  ${\text{Br}}_{\text{2}\left(\text{l}\right)}{\text{+H}}_{\text{2}}{\text{O}}_{\left(\text{l}\right)}\stackrel{}{\to }{\text{HBrO}}_{\left(\text{aq}\right)}{\text{+HBr}}_{\left(\text{aq}\right)}$

In this reaction, the bromine is reduced to bromide ion thus, it is a redox reaction.

The reaction (c) is,

  ${\text{NaCl}}_{\left(\text{s}\right)}{\text{+H}}_{\text{2}}{\text{SO}}_{\text{4}\left(\text{aq}\right)}\stackrel{}{\to }{\text{NaHSO}}_{\text{4}\left(\text{aq}\right)}{\text{+HCl}}_{\left(\text{aq}\right)}$

Sodium chloride is a base and sulfuric acid is an acid.  This is the reaction between an acid and base thus, it is an acid-base reaction.