Most reactive halide towards SN1 reaction isa)n-Butyl chlorideb)sec-B...
SN1 reactions are nucleophilic substitution reactions that proceed through a two-step mechanism. The first step involves the formation of a carbocation intermediate, and the second step involves the attack of a nucleophile on the carbocation. The rate-determining step in SN1 reactions is the formation of the carbocation, so the reactivity of the halide towards SN1 reactions can be determined by the stability of the carbocation intermediate.
In general, more substituted carbocations are more stable than less substituted carbocations. This is because the alkyl groups adjacent to the carbocation can donate electron density through hyperconjugation, which stabilizes the positive charge. Therefore, the more substituted the halide, the more stable the carbocation intermediate, and the more reactive the halide towards SN1 reactions.
In the given options, the tert-butyl chloride (option C) is the most reactive halide towards SN1 reactions. This is because the tert-butyl chloride has a tertiary carbon adjacent to the chloride leaving group. The resulting carbocation intermediate after the departure of the chloride ion is tertiary, which is highly stable due to hyperconjugation effects.
On the other hand, n-butyl chloride (option A) has a primary carbon adjacent to the chloride leaving group, which would result in a less stable primary carbocation intermediate. Similarly, sec-butyl chloride (option B) has a secondary carbon adjacent to the chloride leaving group, leading to a less stable secondary carbocation intermediate. Allyl chloride (option D) has a resonance-stabilized allylic carbocation intermediate, which is more stable than primary or secondary carbocations but less stable than a tertiary carbocation.
Therefore, among the given options, tert-butyl chloride (option C) is the most reactive halide towards SN1 reactions due to the stability of the resulting carbocation intermediate.
Most reactive halide towards SN1 reaction isa)n-Butyl chlorideb)sec-B...
More stable the carbocation, more reactive will be the parent alkyl halide towards SN1 reaction. 3° > Benzyl > Allyl > 2° > 1° > methyl
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