Given below are two statements: Statement (I): Alcohols are formed when alkyl chlorides are treated with aqueous potassium hydroxide by elimination reaction. Statement (II): In alcoholic potassium hydroxide, alkyl chlorides form alkenes by abstracting the hydrogen from the $ \beta $-carbon. In the light of the above statements, choose the most appropriate answer from the options given below:
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Elimination and substitution reactions are key processes for forming alkenes and alcohols, respectively, based on the conditions (e.g., solvent, temperature).
Statement I is incorrect but Statement II is correct
Statement I is correct but Statement II is incorrect
Both Statement I and Statement II are correct
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The Correct Option isB
Solution and Explanation
To address this question, we must evaluate the provided statements concerning the reactions of alkyl chlorides with potassium hydroxide solutions.
Analysis of Statement I:
This statement asserts that alcohols are produced from the reaction of alkyl chlorides with aqueous potassium hydroxide via an elimination reaction.
This assertion is erroneous. While aqueous potassium hydroxide does yield alcohols from alkyl chlorides, the mechanism is a substitution reaction, not elimination. The hydroxide ion (\( \text{OH}^- \)) substitutes the chloride ion (\( \text{Cl}^- \)), forming alcohols.
The corresponding reaction is represented as: \(R-\text{Cl} + \text{KOH(aq)} \rightarrow R-\text{OH} + \text{KCl}\)
Analysis of Statement II:
This statement proposes that alkyl chlorides generate alkenes in the presence of alcoholic potassium hydroxide by abstracting hydrogen from the \( \beta \)-carbon.
This assertion is accurate. Alcoholic KOH induces elimination in alkyl chlorides, leading to the formation of alkenes. This is a dehydrohalogenation reaction, characterized by the removal of hydrogen from the \( \beta \)-carbon and the formation of a double bond.
The reaction is depicted as: \(R-\text{CH}_2-\text{CH}\text{Cl}-R' + \text{KOH(alc)} \rightarrow R-\text{CH}=\text{CH}-R' + \text{KCl} + \text{H}_2\text{O}\)
Based on these analyses:
Statement I is incorrect due to the misidentification of the reaction mechanism (elimination instead of substitution) in alcohol formation.
Statement II is correct as it accurately describes the elimination process yielding alkenes.
Therefore, the correct conclusion is: Statement I is incorrect, while Statement II is correct.
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