Question

19. Functional isomer of but-1-yne is (1) But-2-yne (3) But-2-ene (2) But-1-ene (4) Buta-1,3-diene​

Answer 1

The Functional isomer of but-1-yne is (4) Buta-1,3-diene​.

• Two compounds having the same molecular formula but show different branched structures show chain isomerism.
• The molecular formula of both 1-butyne and 1,3-butadiene is $C_{4}H_{6}$
• But their functional group is different, 1-butyne has a triple bond whereas 1,3-butadiene has a double bond.
• Hence, 1,3-butadiene is the functional isomer of 1-butyne and option 4  is correct.

Answer 2

Answer:

1) isomers are those molecules which have same molecular formula but different molecule arrangement

2) here , butyne is having similar formula as but2yne which is C4H6

3) check that there is no triple bond in any of the other given option .