The substrate is the same in parts a and b, however the mechanism that proceeds is different. Explain how the choice of solvent (acetone vs. methanol) influences the reaction mechanism between benzyl bromide and a nucleophile.

See explanation

Explanation:

The reaction of a benzyl bromide with a nucleophile may proceed by SN1 or SN2 mechanism depending on the nature of the solvent used.

Since SN1 reaction involves the formation of a carbocation, it usually predominates in the presence of a poor nucleophiles and protic solvents. Hence when methanol is used as solvent and a poor nucleophile is used, SN1 mechanism predominates.

However, when acetone which is an aprotic solvent is used in the presence of a good nucleophile, SN2 reaction mechanism predominates.

vanderwaal's forces of attraction are the electrostatic intermolecular forces that exist in a molecule due to the temporary or permanent dipoles that are developed in a molecule. in , the major intermolecular forces are dipole-dipole interactions as the molecule is polar (bent structure). so the vanderwaal's forces of interaction in between molecules are the permanent dipole-dipole interactions that develop due to the dipole that exists in between the polar h - s bond. the positively charged hydrogen atom is attracted towards the negative end of the dipole that is sulfur of the adjacent molecule. therefore, these forces of attraction are relatively stronger than that of london dispersion forces that exist in non polar molecules.

h