Final Answer:
The SN₂ reaction with a less hindered substrate is generally faster compared to a more hindered substrate.
Step-by-step explanation:
In SN₂ (substitution nucleophilic bimolecular) reactions, the rate-determining step involves both the nucleophile and the substrate. The steric hindrance around the reaction center significantly influences the reaction rate.
Less Hindered Substrate:
A less hindered substrate allows the nucleophile to approach the reaction center more easily, resulting in a faster SN₂ reaction.
The steric hindrance is lower, allowing for better nucleophile access and a quicker displacement of the leaving group.
More Hindered Substrate:
In contrast, a more hindered substrate creates a barrier for the nucleophile, making it more difficult for the nucleophile to reach the reaction center.
Steric hindrance slows down the reaction as the nucleophile encounters resistance in displacing the leaving group.
Understanding the effect of steric hindrance on reaction rates is crucial in predicting and designing reaction outcomes in organic chemistry. It helps chemists optimize reaction conditions for desired outcomes and avoid unfavorable reactions due to steric hindrance.