Question

Lucas reagent is

• A. Anhydrous \( \text{CaCl}_2 \) and conc. HCl
• B. Anhydrous \( \text{ZnCl}_2 \) and conc. HCl
• C. Anhydrous \( \text{AlCl}_3 \) and conc. HCl
• D. Anhydrous \( \text{PdCl}_2 \) and conc. HCl

Hint:

Lucas reagent is used to distinguish between primary, secondary, and tertiary alcohols based on their reactivity in the presence of \( \text{ZnCl}_2 \) and conc. HCl.

Answer 1

The Correct Option is B

Step 1: Understanding Lucas reagent.
Lucas reagent is a solution of anhydrous zinc chloride (\( \text{ZnCl}_2 \)) in concentrated hydrochloric acid (HCl). It is used to distinguish between different types of alcohols based on their reactivity. Step 2: Analysis of options.
(A) Anhydrous \( \text{CaCl}_2 \) and conc. HCl: This is incorrect; calcium chloride is not used in Lucas reagent.
(B) Anhydrous \( \text{ZnCl}_2 \) and conc. HCl: Correct — Lucas reagent consists of anhydrous \( \text{ZnCl}_2 \) and conc. HCl.
(C) Anhydrous \( \text{AlCl}_3 \) and conc. HCl: This is incorrect; aluminum chloride is not used in Lucas reagent.
(D) Anhydrous \( \text{PdCl}_2 \) and conc. HCl: This is incorrect; palladium chloride is not used in Lucas reagent.
Step 3: Conclusion.
The correct answer is (B) because Lucas reagent contains anhydrous \( \text{ZnCl}_2 \) and concentrated HCl.