Chapter 9, Problem 9.1P

Interpretation Introduction

(a)

Interpretation:

The expected nucleophilic substitution product formed when methyl iodide reacts with ${\text{Na}}^{+}{\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{S}}^{-}$ is to be stated?

Concept introduction:

A nucleophilic substitution reaction is a reaction in which nucleophile donates an electron pair to an electrophile and replaces leaving group. A general nucleophilic substitution reaction is shown below.

${\text{Nu}}^{-}+\text{R}-\text{X}\to \text{R}-\text{Nu}+{\text{X}}^{-}$

Answer to Problem 9.1P

The expected nucleophilic substitution product formed when methyl iodide reacts with ${\text{Na}}^{+}{\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{S}}^{-}$ is ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{SCH}}_{\text{3}}$.

Explanation of Solution

The nucleophilic atom of ${\text{Na}}^{+}{\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{S}}^{-}$ is sulfur which attacks on the carbon atom of methyl iodide and replaces iodine as iodide ion. The product formed is ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{SCH}}_{\text{3}}$. The reaction of methyl iodide with ${\text{Na}}^{+}{\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{S}}^{-}$ is shown below.

${\text{Na}}^{+}{\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{S}}^{-}+{\text{CH}}_{\text{3}}-\text{I}\to {\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}-\text{S}-{\text{CH}}_{\text{3}}+{\text{Na}}^{+}{\text{I}}^{-}$

Conclusion

The expected nucleophilic substitution product formed when methyl iodide reacts with ${\text{Na}}^{+}{\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{S}}^{-}$ is ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{SCH}}_{\text{3}}$.

Interpretation Introduction

(b)

Interpretation:

The expected nucleophilic substitution product formed when ethyl iodide reacts with ammonia is to be stated.

Concept introduction:

A nucleophilic substitution reaction is a reaction in which nucleophile donates an electron pair to an electrophile and replaces leaving group. A general nucleophilic substitution reaction is shown below.

${\text{Nu}}^{-}+\text{R}-\text{X}\to \text{R}-\text{Nu}+{\text{X}}^{-}$

Answer to Problem 9.1P

The expected nucleophilic substitution product formed when ethyl iodide reacts with ammonia is ethyl ammine $\left({\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{NH}}_{\text{2}}\right)$.

Explanation of Solution

The nucleophile is ammonia $\left({\text{NH}\stackrel{}{¨}}_{\text{3}}\right)$ in this reaction. The lone pair of ammonia that is present at nitrogen atom attacks on the carbon atom of ethyl iodide and replace iodine as iodide ion. The product formed is ethyl ammine $\left({\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{NH}}_{\text{2}}\right)$. The reaction of ethyl iodide reacts with ammonia is shown below.

${\text{NH}\stackrel{}{¨}}_{\text{3}}+{\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}-\text{I}\to {\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}-{\text{NH}}_{\text{2}}+{\text{H}}^{+}{\text{I}}^{-}$

Conclusion

The expected nucleophilic substitution product formed when ethyl iodide reacts with ammonia is ethyl ammine $\left({\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{NH}}_{\text{2}}\right)$.