Chapter 3, Problem 3.1P

Interpretation Introduction

(a)

Interpretation:

The structure for the product of each of the given Lewis acid-base association reactions is to be derived by using curved-arrow notation. The formal charge on each species is to be assigned. The Lewis acid and the Lewis base is to be labeled. The atom that donates electrons in each case is to be predicted.

Concept introduction:

Lewis acid-base association reaction involves the transfer of a proton from a base to an acid. Lewis acid accepts an electron pair and acts as an electrophile. Lewis base donates an electron pair and acts as a nucleophile.

Answer to Problem 3.1P

The Lewis acid and Lewis base are $\left({\text{CH}}_{\text{3}}\right){\text{C}}^{+}$ and ${\text{H}}_{\text{2}}\text{O}$ respectively. The atom that donates electrons is oxygen. The curved-arrow notation for given Lewis acid-base association reactions is,

Explanation of Solution

Lewis acids are electron donor, whereas Lewis bases are electron pair accepter. In water molecule oxygen consists of a lone pair. Thus, it will act a Lewis base and oxygen atom has tendnecy to donate its electrons. The $\left({\text{CH}}_{\text{3}}\right){\text{C}}^{+}$ is an electron deficient specie. Thus, it will act as a Lewis acid.

The oxygen in ${\text{H}}_{\text{2}}\text{O}$ donates its electron to $\left({\text{CH}}_{\text{3}}\right){\text{C}}^{+}$ andin bond formation ${\text{H}}_{\text{2}}\text{O}$, holds a one unit positive formal charge, whereas $\left({\text{CH}}_{\text{3}}\right){\text{C}}^{+}$ accepts the electrons and becomes neutral. The curved-arrow notation for given Lewis acid-base association reactions is shown below.

Figure 1

Conclusion

The Lewis acid and Lewis base are $\left({\text{CH}}_{\text{3}}\right){\text{C}}^{+}$ and ${\text{H}}_{\text{2}}\text{O}$ respectively. The atom that donates electrons is oxygen to $\left({\text{CH}}_{\text{3}}\right){\text{C}}^{+}$. The curved-arrow notation for given Lewis acid-base association reactions is shown in Figure 1.

Interpretation Introduction

(b)

Interpretation:

The structure for the product of each of the given Lewis acid-base association reactions is to be derived by using curved-arrow notation. The formal charge on each species is to be assigned. The Lewis acid and the Lewis base is to be labeled. The atom that donates electrons in each case is to be predicted.

Concept introduction:

Lewis acid-base association reaction involves the transfer of a proton from a base to an acid. Lewis acid accepts an electron pair. It acts as an electrophile Lewis base donates an electron pair. It acts as nucleophile.

Answer to Problem 3.1P

The Lewis acid and Lewis base are ${\text{BF}}_{\text{3}}$ and ${\text{NH}}_3$ respectively. The atom that donates electrons is nitrogen. The curved-arrow notation for given Lewis acid-base association reactions is,

Explanation of Solution

Lewis acids are electron donor, whereas Lewis bases are electron accepter. In ${\text{NH}}_3$ molecule, nitrogen consists of lone pairs. Thus, it will act a Lewis base and nitrogen atom will donate its electrons. The ${\text{BF}}_{\text{3}}$ is an electron deficient species. Thus, it will act as Lewis acid.

The nitrogen in ${\text{NH}}_3$ donates its electron to ${\text{BF}}_{\text{3}}$ and in bond formation ${\text{NH}}_3$ holds an one unit postive formal charge, whereas ${\text{BF}}_{\text{3}}$ accepts an electron and holds a one negative formal charge. The curved-arrow notation for given Lewis acid-base association reactions is shown below.

Figure 2

Conclusion

The Lewis acid and Lewis base are ${\text{BF}}_{\text{3}}$ and ${\text{NH}}_3$ respectively. The atom that donates electrons is nitrogen. The curved-arrow notation for given Lewis acid-base association reactions is shown in Figure 2.