SN1 reaction

- SN1 reaction is a type of nucleophilic substitution reaction in which the rate-determining step involves the formation of a carbocation intermediate.
- The reaction proceeds in two steps: first, the leaving group departs from the substrate to form a carbocation intermediate, and then the nucleophile attacks the carbocation to form the product.
- This reaction is favored by the presence of a polar solvent and a good leaving group.

Option B: SN1 reaction would be faster in ethanol than in pentane

- Ethanol is a polar solvent that stabilizes the carbocation intermediate by solvation.
- The polar solvent also stabilizes the transition state by reducing the energy required for the nucleophile to attack the carbocation intermediate.
- Pentane, on the other hand, is a nonpolar solvent that cannot stabilize the carbocation intermediate or the transition state.
- Therefore, the reaction would proceed faster in ethanol than in pentane.

Option A: SN1 reaction would be faster at 25C than at 50C

- SN1 reaction is a first-order reaction, which means that the rate of the reaction depends only on the concentration of the substrate.
- The rate constant of the reaction is temperature-dependent, with higher temperatures leading to higher reaction rates.
- Therefore, the reaction would be faster at 50C than at 25C.

Option C: Keeping the moles of reactants constant but doubling the quantity of solvent would decrease the rate by a factor of 4

- Doubling the quantity of solvent would decrease the concentration of the substrate in the solution.
- Since the reaction rate depends on the concentration of the substrate, decreasing the concentration would decrease the reaction rate.
- However, the rate would not decrease by a factor of 4, as the rate of the reaction is proportional to the concentration of the substrate, not the quantity of solvent.

Option D: Stereochemical inversion occurs exclusively

- SN1 reaction does not involve a concerted mechanism, which means that the nucleophile attacks the carbocation from any direction.
- Therefore, the product can have different stereochemical configurations, depending on the orientation of the nucleophile.
- However, if the substrate is chiral, the reaction can lead to a mixture of enantiomers, with each enantiomer having the opposite configuration of the other.