Lucas test: telling 1°, 2° and 3° alcohols apartल्यूकास परीक्षण: 1°, 2° और 3° ऐल्कोहॉल में अंतरLucas test: telling 1°, 2° and 3° alcohols apart

Class 12 Chemistry · Chapter 7 · interactive diagram

Parts and what they mean

• Tertiary alcohol: turbidity immediately (तृतीयक ऐल्कोहॉल: तुरंत धुंधलापन) — Tertiary alcohols form the alkyl halide most easily (stable 3° carbocation).
• Secondary alcohol: turbidity after a few minutes (द्वितीयक ऐल्कोहॉल: कुछ मिनट बाद धुंधलापन) — NCERT states only the 3° and 1° results; 2° alcohols react at an intermediate rate (typically within about 5 minutes).
• Primary alcohol: no turbidity at room temperature (प्राथमिक ऐल्कोहॉल: कमरे के ताप पर धुंधलापन नहीं) — The solution stays clear (reaction needs heating).
• Why turbidity appears (धुंधलापन क्यों आता है) — The alkyl chloride does not dissolve in the reagent and separates as a cloudy layer.
• Reaction with hydrogen halide (हाइड्रोजन हैलाइड से अभिक्रिया) — ROH + HX → R–X + H₂O; the rate differs for the three classes.

Original diagram drawn by Simple Learning Hub, based on the NCERT textbook. Report a mistake