Chapter 9: Q107P (page 391)

which solvent—ethanol or diethyl ether—would the equilibrium for the following SN2 reaction lie farther to the right?

Short Answer

Expert verified

Ethanol will undergo equilibrium for the following SN2 reaction lie further to the right because it is a polar protic solvent and it increases the reaction rate for neutral nucleophile more than the charged nucleophiles.

Step by step solution

General rule of polarity with nature of nucleophile

The way a change in the polarity of the solvent affects the rate of a reaction does not

depend on the mechanism of the reaction. It depends only on whether the reactants that participate in the rate-determining step are charged or neutral. Therefore,

An SN2 or E2 reaction of an alkyl halide with a charged nucleophile/base should be carried out in an aprotic polar solvent.
An SN2 or E2 reaction of an alkyl halide with a neutral nucleophile/base should be carried out in a polar solvent.

Reason

In the above reaction, the nucleophile used in the reaction is neutral, So the reaction rate will increase in polar protic solvent more than polar aprotic solvent.

Between ethanol and diethyl ether, ethanol has a H directly attached to O which can make H bonding whereas it kind of bond is not applicable for Diethyl ether. Thus, ethanol becomes a polar protic solvent and undergo SN2 reaction more readily than using diethyl ether.