Chapter 6, Problem 6.39P

Interpretation Introduction

(a)

Interpretation:

Missing curved arrows are to be supplied for the given proton transfer reaction. The relevant electrons are to be drawn if they are not shown.

Concept introduction:

In a proton transfer reaction, a proton is transferred from a Bronsted-Lowry acid to a Bronsted-Lowry base in a single elementary step in which one bond is broken and another is formed simultaneously. The curved arrow notation shows the movement of valence electrons, not atoms. The movement of two electrons is shown be using a double-barbed arrow. To represent bond breaking, the tail of the arrow originates from the center of a bond whereas to represent bond formation, the head of arrow points to an atom which forms the new bond, that is, σ bond or the region where the bond is formed if the new bond is a π bond.

Answer to Problem 6.39P

The missing curved arrow notation for the proton transfer reaction and relevant electrons is shown as

Explanation of Solution

The given proton transfer reaction is

In the above reaction, the bond $\text{(C-H)}$ is formed between the C of the first reactant and H of water. Also, ${\text{H}}_{\text{2}}\text{O}$ donates a proton and forms its conjugate base, i.e., ${\text{HO}}^{\text{-}}$, so one O-H bond of ${\text{H}}_{\text{2}}\text{O}$ is broken. The bond breaking and bond formation involve only valence electrons, so first all valence electrons in the given two reactants should be drawn. From that, it is clearly seen which electrons are involved in the reaction, both from the reactants and from the products, as shown below:

The appropriate movement of these valence electrons is shown by using curved arrow notations. One curved arrow is to be drawn from the lone pair on C to the H on water (highlighted blue) to illustrate the formation of $\text{H-C}$ bond. A second curved arrow originates from the center of the $\text{O-H}$ bond to illustrate the breaking of that bond and points to the O atom, showing that those electrons end up as a lone pair on O. Therefore, the curved arrow notation for the proton transfer reaction is as follows:

Conclusion

The curved arrow notation for the proton transfer of the given reaction is drawn on the basis of the movement of valence electrons involved in bond breaking and bond formation.

Interpretation Introduction

(b)

Interpretation:

Missing curved arrows are to be supplied for the given proton transfer reaction. The relevant electrons are to be drawn if they are not shown.

Concept introduction:

In a proton transfer reaction, a proton is transferred from a Bronsted-Lowry acid to a Bronsted-Lowry base in a single elementary step in which one bond is broken and another is formed simultaneously. The curved arrow notation shows the movement of valence electrons, not atoms. The movement of two electrons is shown be using a double-barbed arrow. To represent bond breaking, the tail of the arrow originates from the center of a bond whereas to represent bond formation, the head of arrow points to an atom which forms the new bond, that is, bond or the region where the bond is formed if the new bond is a bond.

Answer to Problem 6.39P

The missing curved arrow notation for the proton transfer reaction and relevant electrons is shown as

Explanation of Solution

The given proton transfer reaction is

In the above reaction, the bond $\text{(O-H)}$ is formed between the O of the second reactant and the H of the first reactant. Also, the first reactant donates a proton and forms its conjugate base, so one $\text{N-H}$ bond of the first reactant is broken. The bond breaking and bond formation involve only valence electrons, so first all valence electrons in the given two reactants should be drawn. From that, it is clearly seen which electrons are involved in the reaction, both from the reactants and from the products, as shown below:

The appropriate movement of these valence electrons is shown by using curved arrow notations. One curved arrow is to be drawn from the lone pair on O to the H on N (highlighted blue) to illustrate the formation of the $\text{O-H}$ bond. A second curved arrow originates from the center of the $\text{N-H}$ bond to illustrate the breaking of that bond and points to the N atom, showing that those electrons end up as a lone pair on N. Therefore, the curved arrow notation for the proton transfer reaction is as follows:

Conclusion

The curved arrow notation for the proton transfer of the given reaction is drawn on the basis of the movement of valence electrons involved in bond breaking and bond formation.

Interpretation Introduction

(c)

Interpretation:

Missing curved arrows are to be supplied for the given proton transfer reaction. The relevant electrons are to be drawn if they are not shown.

Concept introduction:

In a proton transfer reaction, a proton is transferred from a Bronsted-Lowry acid to a Bronsted-Lowry base in a single elementary step in which one bond is broken and another is formed simultaneously. The curved arrow notation shows the movement of valence electrons, not atoms. The movement of two electrons is shown be using a double-barbed arrow. To represent bond breaking, the tail of the arrow originates from the center of a bond whereas to represent bond formation, the head of arrow points to an atom which forms the new bond, that is, bond or the region where the bond is formed if the new bond is a bond.

Answer to Problem 6.39P

The missing curved arrow notation for the proton transfer reaction and relevant electrons is shown as

Explanation of Solution

The given proton transfer reaction is

In the above reaction, the bond $\text{(N-H)}$ is formed between the N of the second reactant and the H of the first reactant. Also, the first reactant donates a proton and forms its conjugate base, so one $\text{C-H}$ bond of the methyl group of the first reactant is broken. The bond breaking and bond formation involve only valence electrons, so first all valence electrons in the given two reactants should be drawn. From that, it is clearly seen which electrons are involved in the reaction, both from the reactants and from the products, as shown below:

The appropriate movement of these valence electrons is shown by using curved arrow notations. One curved arrow is to be drawn from the lone pair on N to the H on C (highlighted blue) to illustrate the formation of the $\text{N-H}$ bond. A second curved arrow originates from the center of the $\text{C-H}$ bond to illustrate the breaking of that bond and points to the C atom, showing that those electrons end up as a lone pair on C. Therefore, the curved arrow notation for the proton transfer reaction is as follows:

Conclusion

The curved arrow notation for the proton transfer of the given reaction is drawn on the basis of the movement of valence electrons involved in bond breaking and bond formation.

Interpretation Introduction

(d)

Interpretation:

Missing curved arrows are to be supplied for the given proton transfer reaction. The relevant electrons are to be drawn if they are not shown.

Concept introduction:

In a proton transfer reaction, a proton is transferred from a Bronsted-Lowry acid to a Bronsted-Lowry base in a single elementary step in which one bond is broken and another is formed simultaneously. The curved arrow notation shows the movement of valence electrons, not atoms. The movement of two electrons is shown be using a double-barbed arrow. To represent bond breaking, the tail of the arrow originates from the center of a bond whereas to represent bond formation, the head of arrow points to an atom which forms the new bond, that is, bond or the region where the bond is formed if the new bond is a bond.

Answer to Problem 6.39P

The missing curved arrow notation for the proton transfer reaction and relevant electrons is shown as

Explanation of Solution

The given proton transfer reaction is

In the above reaction, the bond $\text{(O-H)}$ is formed between the O of the first reactant and the H of the ${\text{H}}_{\text{3}}{\text{O}}^{\text{+}}$ ion. Also, ${\text{H}}_{\text{3}}{\text{O}}^{\text{+}}$ donates a proton and forms its conjugate base as ${\text{H}}_{\text{2}}\text{O}$, so one $\text{O-H}$ bond of ${\text{H}}_{\text{3}}{\text{O}}^{\text{+}}$ is broken. The bond breaking and bond formation involve only valence electrons, so first, all valence electrons in the given two reactants should be drawn. From that, it is clearly seen which electrons are involved in the reaction, both from the reactants and from the products, as shown below,

The appropriate movement of these valence electrons is shown by using curved arrow notations. One curved arrow is to be drawn from the lone pair on O to the H of ${\text{H}}_{\text{3}}{\text{O}}^{\text{+}}$ ion (highlighted blue) to illustrate the formation of the $\text{O-H}$ bond. A second curved arrow originates from the center of the $\text{O-H}$ bond to illustrate the breaking of that bond and points to the O atom, showing that those electrons end up as a lone pair on O. Therefore, the curved arrow notation for the proton transfer reaction is as follows:

Conclusion

The curved arrow notation for the proton transfer of the given reaction is drawn on the basis of the movement of valence electrons involved in bond breaking and bond formation.