BITSAT2024ChemistryAlcohols Phenols and EthersActual
An unknown alcohol is treated with the "Lucas reagent" to determine whether the alcohol is primary, secondary or tertiary. Which alcohol reacts fastest and by what mechanism :
Options
- Asecondary alcohol by S _ N 1
- Btertiary alcohol by S _ N 1
- Csecondary alcohol by S _ N 2
- Dtertiary alcohol by S _ N 2
Correct answer
B. tertiary alcohol by S _ N 1
Step-by-step solution
The reaction of alcohol with Lucas reagent is mostly an S _ N 1 mechanism reaction and the rate of reaction is directly proportional to the carbocation stability formed in the reaction, hence tertiary alcohol will react fastest.