Chapter 20, Problem 24A

(a)

Interpretation Introduction

Interpretation:

The missing molecule in followingsubstitution reactionhas to be indicated:

  ${\text{CH}}_{\text{4}}{\text{ + Cl}}_{\text{2}}\stackrel{\text{hv}}{\to }\text{HCl + ?}$

Concept Introduction:

Substitution reactionis defined as one type of chemical reaction when one atomor one group in a compound is replaced by another atom or group. When a hydrogen atom in an alkaneis replaced by a halogenatom (Cl, Br, I)is called halogenation.

Answer to Problem 24A

The missing molecule in the given substitution reaction is CH₃Cl.

  

Explanation of Solution

When a hydrogen atom in an alkane is replaced by a halogen atom (Cl, Br, I) is called halogenation.

When methane is treated with chlorine molecule, one hydrogen of methane is replaced by chlorine atom and this occurs in presence of light. The reaction occurs via free radical mechanism. Light converts chlorine molecule into chlorine radical into chain initiation step which then combines with methane and convert it into methyl chloride.

  

(b)

Interpretation Introduction

Interpretation:

The missing molecule in following substitution reaction has to be indicated:

  ${\text{CH}}_2{\text{Cl}}_{\text{2}}{\text{ + Cl}}_{\text{2}}\stackrel{\text{hv}}{\to }{\text{CHCl}}_3\text{ + ?}$

Concept Introduction:

Substitution reaction is defined as one type of chemical reaction when one atomor one group in a compound is replaced by another atom or group. When a hydrogen atom in an alkaneis replaced by a halogen atom (Cl, Br, I)is called halogenation.

Answer to Problem 24A

The missing molecule in the given substitution reaction is HCl.

  

Explanation of Solution

When a hydrogen atom in an alkane is replaced by a halogen atom (Cl, Br, I) is called halogenation.

When dichloromethane is treated with chlorine molecule, one hydrogen of dichloromethane is replaced by chlorine atom and this occurs in presence of light. The reaction occurs via free radical mechanism. Light converts chlorine molecule into chlorine radical into chain initiation step which then combines with dichloromethane and convert it into trichloromethane.

  

(c)

Interpretation Introduction

Interpretation:

The missing molecule in following substitution reaction has to be indicated:

  ${\text{? + Cl}}_{\text{2}}\stackrel{\text{hv}}{\to }{\text{CCl}}_{\text{4}}\text{+ HCl}$

Concept Introduction:

Substitution reaction is defined as one type of chemical reaction when one atomor one group in a compound is replaced by another atom or group. When a hydrogen atom in an alkaneis replaced by a halogen atom (Cl, Br, I)is called halogenation.

Answer to Problem 24A

The missing molecule in the given substitution reaction is CHCl₃.

  

Explanation of Solution

When a hydrogen atom in an alkane is replaced by a halogen atom (Cl, Br, I) is called halogenation.

When trichloromethane is treated with chlorine molecule, one hydrogen of trichloromethane is replaced by chlorine atom and this occurs in presence of light. The reaction occurs via free radical mechanism. Light converts chlorine molecule into chlorine radical into chain initiation step which then combines with trichloromethane and convert it into tetrachloromethane.

  

(d)

Interpretation Introduction

Interpretation:

The missing molecule in following substitution reaction has to be indicated:

  ${\text{CH}}_3\text{Cl + ? }\stackrel{\text{hv}}{\to }{\text{CH}}_2{\text{Cl}}_2\text{ + HCl}$

Concept Introduction:

Substitution reaction is defined as one type of chemical reaction when one atomor one group in a compound is replaced by another atom or group. When a hydrogen atom in an alkaneis replaced by a halogen atom (Cl, Br, I)is called halogenation.

Answer to Problem 24A

The missing molecule in the given substitution reaction is Cl₂.

  

Explanation of Solution

When a hydrogen atom in an alkane is replaced by a halogen atom (Cl, Br, I) is called halogenation.

When chloromethane is treated with chlorine molecule, one hydrogen of chloromethane is replaced by chlorine atom and this occurs in presence of light. The reaction occurs via free radical mechanism. Light converts chlorine molecule into chlorine radical into chain initiation step which then combines with chloromethane and convert it into dichloromethane.