How will you distinguish between 1-propanol and 2-propanol by a suitable chemical test?
Answer: Iodoform test: 2-propanol (CH₃–CHOH–) gives yellow CHI₃ with I₂/NaOH; 1-propanol does not. (Lucas test also acceptable.)
Solution
Iodoform test — warm each with I and NaOH:
2-Propanol has the CH–CH(OH)– unit → yellow precipitate of iodoform, CHI.
1-Propanol lacks it → no precipitate.
(Alternatively, Lucas reagent: 2-propanol turbid in ~5 min; 1-propanol only on heating.)
2-Propanol has the CH–CH(OH)– unit → yellow precipitate of iodoform, CHI.
1-Propanol lacks it → no precipitate.
(Alternatively, Lucas reagent: 2-propanol turbid in ~5 min; 1-propanol only on heating.)
CBSE Class 12 Board · 2003 · All India Compartment · Subjective