Single Choice

Which of the following alcohols reacts most readily with Lucas reagent?

A$$ CH_3CH_2CH_2OH$$
B$$CH_3-\underset{OH}{\underset{|}CH}-CH_3$$
C$$CH_3-\overset{CH_3}{\overset{|}{\underset{OH}{\underset{|}C}}-}CH_{3}$$
Correct Answer
D$$CH_3-\underset{CH_3}{\underset{|}CH}-CH_2OH$$

Solution

Lucas test is a test to recognize whether the given alcohol is primary, secondary or tertiary in nature. Lucas reagent is a mixture of conc. $$HCl$$ and dry anhydrous $$ZnCl_2$$. In this reaction, carbocation is formed as an intermediate and thus the stability and ease of carbocation formation determine the rate of the reaction as that's the slow step of the mechanism. Hence the order of reactivity is tertiary alcohol>secondary alcohol>primary alcohol by $$S_N1$$ mechanism. Thus $$C(CH_3)_3OH$$ being tertiary alcohol will react most readily with Lucas reagent.

SIMILAR QUESTIONS

Alcohols, Phenols and Ethers

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?

Alcohols, Phenols and Ethers

From amongst the following alcohols the one that would react fastest with conc. $$HCl$$ and anhydrous $${Z}n{C}l_{2}$$, is:

Alcohols, Phenols and Ethers

An alcohol gave Lucas test in about 5 minutes. When the alcohol was treated with hot concentrated $$H_2SO_4$$, it gave an alkene of molecular formula $$C_4H_8$$ which on ozonolysis gives single product with molecular formula $$C_2H_4O$$. The structure of alcohol is:

Alcohols, Phenols and Ethers

Lucas test is given by an alcohol within 5 minutes. 0.22 g of which liberates 56 mL of $$ CH_4$$ at STP on treating with $$CH_3MgI$$.The structure of alcohol is:

Alcohols, Phenols and Ethers

Which of the following compounds reacts immediately with Lucas reagent?

Alcohols, Phenols and Ethers

Which alcohol will give immediate turbidity on shaking with HCl at room temperature?

Alcohols, Phenols and Ethers

An alcohol (A) gives Lucas test within 5 min. 7.4 g of alcohol when treated with sodium metal liberates 1120 mL of $$H_2$$ at STP. What will be alcohol (A)?

Alcohols, Phenols and Ethers

Vinyl chloride and ethyl chloride can be distinguished by:

Alcohols, Phenols and Ethers

Which of the following will react fastest with Lucas reagent?

Alcohols, Phenols and Ethers

Explain the following behavior: Reactivity of all the three classes of alcohols with conc. HCl and $$ZnCl_2$$ is different.

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