The LUCAS REAGENT is used to distinguish between primary, secondary, and tertiary alcohols. It consists of

1. NCERT §7.4 describes the Lucas test. 2. REAGENT: concentrated HCl + anhydrous $\mathrm{ZnCl_2}$ (the Lucas reagent). 3. The test distinguishes alcohols by RATE of formation of alkyl chloride (which appears as TURBIDITY since alkyl chlorides are insoluble in the aqueous reagent). 4. Results: • 3° alcohol: turbidity APPEARS IMMEDIATELY (carbocation forms easily — tertiary carbocations very stable). • 2° alcohol: turbidity in ~5–10 minutes. • 1° alcohol: NO turbidity at room temperature (would need heat). 5. Option B is an oxidising mix (could oxidise alcohols, different test). Options C and D are unrelated chemistry. _Source: NCERT Class 12 Chemistry Part 2, Ch 7, §7.4 (Distinction of 1°, 2°, 3° alcohols — Lucas test), p. 11._