Chapter 9, Problem 9.29P

Interpretation Introduction

Interpretation:

It is to be determined whether ${\text{F}}^{\text{-}}{\text{or I}}^{\text{-}}$ is a stronger nucleophile in ethanol.

Concept introduction:

Nucleophiles are nucleus loving species, which are electron rich and are attracted to electrophiles. The nucleophilicity is the capacity of a nucleophile to react.

In the absence of any solvent, the nucleophilicity depends on an atom carrying a negative charge or lone pair, which can be better at stabilizing the negative charge. In the absence of any solvent, the negative charge is better stabilized on a smaller atom as compared to a larger atom within the group in the periodic table.

Since the polar protic solvents contain at least one hydrogen atom directly bonded to an electronegative atom such as $\text{O-H or N-H}$, they are capable of hydrogen bonding. Polar aprotic solvents are the ones that do not contain a hydrogen atom directly bonded to an electronegative atom.

Polar protic solvents tend to solvate both cations and anions very strongly. Polar aprotic solvents tend to solvate cations very strongly but not anions. Due to this, polar protic solvents decrease or weaken the nucleophilicity of an anion.