2022 Alcohols, Phenols and EthersIdentification of Primary, Secondary and Tertiary Alcohols Easy Question 13 of 65 in Alcohols, Phenols and Ethers

Given below are two statements: Statement I: In Lucas test, primary, secondary and tertiary alcohols are distinguished on the basis of their reactivity with conc. HCl + $ZnCl_2$, known as Lucas Reagent. Statement II: Primary alcohols are most reactive and immediately produce turbidity at room temperature on reaction with Lucas Reagent. In the light of the above statements, choose the most appropriate answer from the options given below:

A Statement I is incorrect but Statement II is correct
B Both Statement I and Statement II are correct
C Both Statement I and Statement II are incorrect
D Statement I is correct but Statement II is incorrect

The answer is D.

Solution

Statement I is correct: 1°, 2° and 3° alcohols are distinguished in the Lucas test by the time taken for turbidity to appear with conc. HCl + anhydrous $ZnCl_2$. Statement II is incorrect: tertiary alcohols are the most reactive and give turbidity immediately; secondary alcohols take about 5 minutes and primary alcohols do not give turbidity at room temperature. Reactivity towards Lucas reagent: 3° > 2° > 1°

Concept Lucas test

Alcohols, Phenols and Ethers in past papers

65 questions from this chapter have appeared across 26 exam years.