Organic Compounds Containing Oxygen: Chemistry | JEE Main
Incorrect method of preparation for alcohols from the following is:
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Hint 1 of 2
What are the primary products obtained from the reductive ozonolysis of an alkene?
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Correct answer
Ozonolysis of alkenes cleaves carbon-carbon double bonds to form aldehydes, ketones, or carboxylic acids, not alcohols.
Option analysis
Why each option works or fails
A · Ozonolysis of alkene.
This option is the correct choice because the question asks for the incorrect method of preparation. Ozonolysis of an alkene yields carbonyl compounds (aldehydes and ketones under reductive workup; carboxylic acids under oxidative workup), making it an invalid route to prepare alcohols directly.
B · Reaction of Ketone with RMgBr followed by hydrolysis.
Believing that nucleophilic addition of a Grignard reagent to a ketone does not yield an alcohol. Addition of a Grignard reagent (RMgBr) to a ketone forms a magnesium alkoxide intermediate, which yields a tertiary alcohol upon acidic hydrolysis.
C · Hydroboration-oxidation of alkene.
Confusing hydroboration-oxidation with an oxidative cleavage reaction that produces carbonyls. Hydroboration-oxidation converts an alkene into an alcohol via anti-Markovnikov syn-hydration.
D · Reaction of alkyl halide with aqueous NaOH.
Believing that reaction of an alkyl halide with aqueous NaOH leads primarily to elimination rather than substitution. Aqueous NaOH acts primarily as a nucleophile with alkyl halides, undergoing nucleophilic substitution (SN2 or SN1) to yield alcohols.
Reviewed route
Solution
StepWorking
✓quick_kill
Reaction of alkyl halides with alcoholic KOH causes dehydrohalogenation (elimination) to yield alkenes rather than alcohols (which require aqueous KOH).
Hints that build this answer step by step
What are the primary products obtained from the reductive ozonolysis of an alkene?
Aldehydes and/or ketones
Which product is obtained when a ketone reacts with a Grignard reagent followed by aqueous acid workup?