Read the passage carefully and answer the Questions. Haloalkanes undergo nucelophilic substitution reactions owing to the polarity of C-X bond. The nucleophile reacts with the haloalkane on the carbon possessing a partial positive charge holding the halogen atom. The halogen atom X is replaced by a nucleophile. Depending on the kinetics and mode of bond breaking, the mechanism can be either $S_N1$ or $S_N2$ reaction. The rate of $S_N1$ reaction is governed by the stability of carbocation and in $S_N2$ reaction, the rate of reaction is governed by steric factor. Chirality is the main factor in both $S_N1$ and $S_N2$. In $S_N1$ reaction, the chirality of alkyl halide is accompanied by racemization of the product, while in $S_N2$ reaction, the product is characterized by inversion of configuration. The structure of alkyl halide and the nature of the solvent also governs the mechanism of the substitution. |
Hydrolysis of 2-Chlorobutane will result in formation of |
(+) 2-Butanol (-) 2-butanol (±) 2-Butanol 2-Butanol |
(±) 2-Butanol |
The correct answer is Option (3) →(±) 2-Butanol 2-Chlorobutane is a secondary alkyl halide. During hydrolysis in aqueous medium, it generally undergoes an Sₙ1 reaction mechanism. Step 1: Formation of carbocation CH₃–CHCl–CH₂–CH₃ → CH₃–CH⁺–CH₂–CH₃ + Cl⁻ A planar secondary carbocation is formed. Step 2: Nucleophilic attack Water (or OH⁻) attacks the carbocation. Since the carbocation is planar, the nucleophile can attack from either side of the plane. Thus two products are formed: • (+)-2-butanol • (−)-2-butanol These two forms are enantiomers. When equal amounts of both are formed, the product is a racemic mixture, represented as: (±) 2-butanol Option C: (±) 2-Butanol Both enantiomers form in equal amounts due to attack on the planar carbocation from either side, producing a racemic mixture. Correct.
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