Question

Why is the reactivity of tertiary alcohol greater than secondary alcohol in SN1 reaction?

Answer 1

Dear Student

Sn1 reactions depend on the stability of the carbocation formed when the Leaving group had left.​​​Tertiary alcohols are more reactive because the increased number of alkyl groups increases the +I effect. Due to this +I effect, the charge density on carbon atom increases and around oxygen atom also. This negative charge density pushes the lone pairs on oxygen atom away.,due to which oxygen atom wants to leave the carbon atom as soon as possible. Hence, the cleavage of C−O bond becomes easier. So, a tertiary carbo cation is formed which is more stable than secondary carbocation.So, since tertiary carbocations are most stable of the secondary carbocations it will have more tendency to undergo Sn1 reaction easily.

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