JEE Mains · Chemistry · STD 12 - 6. Haloalkanes and Haloarenes
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 :
- A secondary alcohol by \({S_{{N^1}}}\)
- B tertiary alcohol by \({S_{{N^1}}}\)
- C secondary alcohol by \({S_{{N^2}}}\)
- D tertiary alcohol by \({S_{{N^2}}}\)
Answer & Solution
Correct Answer
(B) tertiary alcohol by \({S_{{N^1}}}\)
Step-by-step Solution
Detailed explanation
The reaction of alcohol with Lucas reagent is mostly an \({S_{{N^1}}}\) reaction and the rate of reaction is directly proportional to the stability of carbocation formed in the reaction. Since \(3^{o} R-O H\) forms \(3^{o}\) carbocation (most stable), hence it will react fastest.
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