The IUPAC name of allylamine is:

The correct answer is Option (2) → Prop-2-en-1-amine

Allylamine is \( \ce{CH2=CH-CH2-NH2} \): an –\( \ce{NH2} \) group on the allyl group. In the IUPAC system an aliphatic amine is named as an alkanamine: the final ‘e’ of the parent hydrocarbon is replaced by ‘amine’, and the chain is numbered so that the carbon carrying –NH₂ gets the lowest number.

Numbering starts at the \( \ce{CH2} \) that carries –\( \ce{NH2} \) (C-1), so the double bond lies between C-2 and C-3. A three-carbon chain with a double bond starting at C-2 is prop-2-ene, and the –\( \ce{NH2} \) is on C-1. The name is prop-2-en-1-amine. Prop-1-en-3-amine numbers the chain from the wrong end, and prop-2-en-2-amine, \( \ce{CH2=C(NH2)-CH3} \), and prop-1-en-1-amine, \( \ce{CH3-CH=CH-NH2} \), are different compounds.

NCERT (2026-27 edition):
Nomenclature – …

Note: The same/similar question has been asked in different years by NTA as per the details given below: