In SN1 reactions, which step is rate-determining?

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Multiple Choice

In SN1 reactions, which step is rate-determining?

In SN1 reactions the rate-determining step is the formation of the carbocation. This is the slow, rate-limiting event where the leaving group departs, generating a highly reactive carbocation intermediate. Once that carbocation exists, the nucleophile can attack, deprotonation to give the final product, and any rearrangements occur rapidly in comparison. Because the rate law for SN1 depends only on the substrate concentration, it reflects this slow ionization step, not the subsequent fast steps. So, the key idea is that breaking the bond to the leaving group to form the carbocation controls how fast the reaction proceeds.

In SN1 reactions the rate-determining step is the formation of the carbocation. This is the slow, rate-limiting event where the leaving group departs, generating a highly reactive carbocation intermediate. Once that carbocation exists, the nucleophile can attack, deprotonation to give the final product, and any rearrangements occur rapidly in comparison. Because the rate law for SN1 depends only on the substrate concentration, it reflects this slow ionization step, not the subsequent fast steps. So, the key idea is that breaking the bond to the leaving group to form the carbocation controls how fast the reaction proceeds.

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