Question

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 +ZnCl₂, knowns 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. Both statement I and Statement II are correct
• B. Both statement I and Statement II are incorrect
• C. Statement I is correct but Statement II is incorrect
• D. Statement I is incorrect but statement II is correct

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
The Lucas test is used to differentiate between \(1^{\circ}, 2^{\circ},\) and \(3^{\circ}\) alcohols. It works on the principle of the formation of alkyl chlorides, which are insoluble in the reagent and cause turbidity.
Detailed Explanation:
Statement I: Lucas reagent is indeed a mixture of concentrated \(HCl\) and anhydrous \(ZnCl_{2}\). It reacts with alcohols to form alkyl halides. This statement is correct.
Statement II: The reactivity of alcohols towards Lucas reagent follows the order: \(3^{\circ}>2^{\circ}>1^{\circ}\).
- Tertiary alcohols produce turbidity immediately.
- Secondary alcohols produce turbidity in 5 minutes.
- Primary alcohols do not produce turbidity at room temperature (only on heating).
Therefore, Statement II is incorrect.
Step 2: Final Answer:
Statement I is correct, and Statement II is incorrect. Option (3) is correct.