Chapter 8.3, Problem 4RQ

(a)

Interpretation Introduction

Interpretation :

Reaction of lead nitrate and potassium iodide must be classified as precipitation reaction, acid-base reaction or oxidation-reduction reaction.

Concept Introduction :

In precipitation reaction two soluble substances react to produce one insoluble product via double decomposition reaction.

In acid-base reaction salt and water is produced.

In oxidation-reduction reaction change in oxidation number take place.

Answer to Problem 4RQ

Reaction of lead nitrate and potassium iodide can be classified as precipitation reaction.

Explanation of Solution

  ${\text{Pb(NO}}_{\text{3}}{\text{)}}_{\text{2}}\text{(aq)+KI(aq)}\to {\text{PbI}}_{\text{2}}{\text{(s)+KNO}}_{\text{3}}\text{(aq)}\text{.}$

In this reaction two soluble salts Pb (NO₃)₂ and KI produce an insoluble salt which is PbI₂. Thus, it is a precipitation reaction.

b)

Interpretation Introduction

Interpretation :

Reaction of nitrogen and hydrogen to produce ammonia must be classified as precipitation reaction, acid-base reaction or oxidation-reduction reaction.

Concept Introduction :

In precipitation reaction two soluble substances react to produce one insoluble product via double decomposition reaction.

In acid-base reaction salt and water is produced.

In oxidation-reduction reaction change in oxidation number take place.

Answer to Problem 4RQ

Reaction of nitrogen and hydrogen to produce ammonia can be classified as oxidation-reduction reaction.

Explanation of Solution

  ${\text{N}}_{\text{2}}{\text{(g)+H}}_{\text{2}}\text{(g)}\to {\text{NH}}_3\text{(g)}\text{.}$

In this reaction nitrogen is reduced by hydrogen as the oxidation number of N is changed from 0 (in N₂) to -3 (in NH₃). The oxidation number of H is increased from 0 (in H₂) to +3 (in NH₃). Thus, it is an oxidation-reduction reaction.

c)

Interpretation Introduction

Interpretation :

Decomposition of KClO₃ to produce potassium chloride and oxygen must be classified as precipitation reaction, acid-base reaction or oxidation-reduction reaction.

Concept Introduction :

In precipitation reaction two soluble substances react to produce one insoluble product via double decomposition reaction.

In acid-base reaction salt and water is produced.

In oxidation-reduction reaction change in oxidation number take place.

Answer to Problem 4RQ

Decomposition of KClO₃ to produce potassium chloride and oxygen can be classified as oxidation-reduction reaction.

Explanation of Solution

  ${\text{KClO}}_{\text{3}}\text{(s)}\to {\text{KCl(s)+O}}_{\text{2}}\text{(g)}\text{.}$

In this reaction oxidation state of Cl is decreased from +5 (in KClO₃) to -1 (in KCl). This is a reduction process. Oxidation state of O is increased from -2 (KClO₃) to 0 (in O₂). It is an oxidation process.

Thus, it is an oxidation-reduction reaction.

d)

Interpretation Introduction

Interpretation :

Reaction of hydrofluoric acid and potassium hydroxide to produce potassium fluoride and water must be classified as precipitation reaction, acid-base reaction or oxidation-reduction reaction.

Concept Introduction :

In precipitation reaction two soluble substances react to produce one insoluble product via double decomposition reaction.

In acid-base reaction salt and water is produced.

In oxidation-reduction reaction change in oxidation number take place.

Answer to Problem 4RQ

Reaction of hydrofluoric acid and potassium hydroxide to produce potassium fluoride and water can be classified as acid-base reaction.

Explanation of Solution

  $\text{HF(aq)+KOH(aq)}\to {\text{KF(aq)+H}}_{\text{2}}\text{O(l)}\text{.}$

In this reaction acid (HF) and base (KOH) react to produce salt (KF) and water.

Thus it is an acid-base reaction.