Question

Which of the following reagents is used to distinguish primary, secondary, and tertiary alcohols?

• A. Lucas Test reagent
• B. Hunsdiecker reagent
• C. Grignard Reaction reagent
• D. Benedict's reagent

Hint:

Remember the 3-2-1 rule for Lucas reagent: 3 (Instant), 2 (5-10 mins), 1 (No reaction at room temp).

Answer 1

The Correct Option is A

Step 1: Concept
In image_a0b3a0.jpg, the objective is to identify a chemical test that provides distinct observable results for $1^\circ$, $2^\circ$, and $3^\circ$ alcohols based on their reactivity.

Step 2: Meaning
Lucas reagent is a solution of anhydrous zinc chloride ($ZnCl_2$) in concentrated hydrochloric acid ($HCl$). It reacts with alcohols to form alkyl chlorides, which are insoluble and create cloudiness (turbidity) in the solution.

Step 3: Analysis
The rate of this reaction depends on the stability of the carbocation formed: * Tertiary ($3^\circ$) alcohols react immediately, producing turbidity instantly. * Secondary ($2^\circ$) alcohols react within 5 to 10 minutes. * Primary ($1^\circ$) alcohols do not produce turbidity at room temperature.

Step 4: Conclusion
Because each class of alcohol reacts at a significantly different speed, the Lucas Test reagent is the standard choice for distinguishing them. Final Answer: (A)