The treatment of alkyl chlorides with aq | Class 12 Chemistry Chapter Haloalkanes and Haloarenes, Haloalkanes and Haloarenes NCERT Solutions

Q20.

The treatment of alkyl chlorides with aqueous KOH leads to the formation of alcohols but in the presence of alcoholic KOH, alkenes are major products. Explain.

In an aqueous solution, KOH almost completely ionizes to give OH - ions. OH - ion is a strong nucleophile, which leads the alkyl chloride to undergo a substitution reaction to form alcohol.

On the other hand, an alcoholic solution of KOH contains alkoxide (RO - ) ion, which is a strong base. Thus, it can abstract a hydrogen from the β-carbon of the alkyl chloride and form an alkene by eliminating a molecule of HCl.

OH - ion is a much weaker base than RO - ion. Also, OH - ion is highly solvated in an aqueous solution and as a result, the basic character of OH - ion decreases. Therefore, it cannot abstract a hydrogen from the β-carbon.

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This question is important because it tests key concepts from the NCERT syllabus and is frequently asked in CBSE exams.

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What is the correct answer to: The treatment of alkyl chlorides with aqueous KOH leads to the formation of alcohols but in the presence of alcoholic KOH, alkenes are major products. Explain.?

In an aqueous solution, KOH almost completely ionizes to give OH - ions. OH - ion is a strong nucleophile, which leads the alkyl chloride to undergo a substitution reaction to form alcohol.



On the other hand, an a...

How do you solve The treatment of alkyl chlorides with aqueous KOH leads to the formation of alcohols but in the presence of alcoholic KOH, alkenes are major products. Explain. step by step?

Step-by-step explanation:
• In an aqueous solution, KOH almost completely ionizes to give OH - ions
• OH - ion is a strong nucleophile, which leads the alkyl chloride to undergo a substitution reaction to form alcohol


What common mistakes should be avoided in this question?

Students often lose marks by skipping steps, writing incomplete explanations, or misunderstanding keywords used in the question.

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Student Discussion

Himani Shukla
Class · · , · Mar 10, 2019
Basic medium does not mean RO-. There can be many sources of OH-. Poor explanation..
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Rajan lubana
Class · · , · Mar 09, 2019
After searching in diff sites finally find a perfect answer to the question
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Paresh
Class · · , · Feb 15, 2019
Thanks for making me understand
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Mother diary
Class · · , · Feb 02, 2018
Ghosh
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