Chapter 6, Problem 6.2P

Interpretation Introduction

Interpretation:

The curved arrow notation is to be drawn for the proton transfer between ammonium ion ${\text{(NH}}_4{}^{+}\text{)}$ and hydroxide ion ${\text{(OH}}^{\text{-}}\text{)}$, where ammonium ion acts as the acid and hydroxide ion acts as the base.

Concept introduction:

In a proton transfer reaction, a proton is transferred from a Bronsted–Lowry acid ( proton donor) to a Bronsted–Lowry base (proton acceptor) in a single elementary step in which one bond is broken and another is formed simultaneously. The conjugate acid is the species that the base becomes after gaining a proton, and the conjugate base is the species that the acid becomes after losing a proton. The curved arrow notation shows the movement of valence electrons, not atoms. Each double-barbed curved arrow shows the movement of two valence electrons. 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, $\text{σ}$ bond or the region where the bond is formed if the new bond is a $\text{π}$ bond.