Question

What is the name of this molecule?

Answer 1

The triple bond is in the first place, not the 3rd because we have to choose the smallest possible number. That means the name will be: ‘but-1-yne’ or ‘1-butyne’

Answer 2

Answer: But-1-yne

Explanation:

The IUPAC nomenclature of alkynes are given as follows:

Select the longest possible carbon chain.

For the number of carbon atom, we add prefix as 'meth' for 1, 'eth' for 2, 'prop' for 3, 'but' for 4, 'pent' for 5, 'hex' for 6, 'sept' for 7, 'oct' for 8, 'nona' for 9 and 'deca' for 10.

The numbering starts from the end from where the double or triple bond gets lower number. A suffix '-yne' is added at the end of the name after the position of the triple bond.

Hence, the name for given hydrocarbon will be But-1-yne.