Pick the reactions which can be used to distinguish between n-propyl alcohol and isopropyl alcohol.
(A) Haloform reaction
(B) Dehydration
(C) Dehydrogenation with Cu/573 K
(D) Oxidation with $CrO_3$
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → (A), (C) and (D) only
To distinguish n-propyl alcohol (1° alcohol) from isopropyl alcohol (2° alcohol), let's examine each reaction:
(A) Haloform reaction
- Isopropyl alcohol (CH₃–CHOH–CH₃) is oxidized to acetone, which gives the haloform reaction.
- n-Propyl alcohol is oxidized to propionaldehyde, which does not give haloform reaction.
Distinguishes
(B) Dehydration
- n-Propyl alcohol → propene
- isopropyl alcohol → propene
Does NOT distinguish (same product)
(C) Dehydrogenation with Cu/573 K
- n-Propyl alcohol → propionaldehyde (aldehyde)
- isopropyl alcohol → acetone (ketone)
Products are different.
Distinguishes
(D) Oxidation with CrO₃
- n-Propyl alcohol → propionic acid
- isopropyl alcohol → acetone (ketone)
Different products.
Distinguishes
Correct Answer: (A), (C), and (D) only