Answer
(1) C2H2 is an alkyne
Explanation
The alkynes are hydrocarbons with triple bond/s.
(1) Has a triple bond
(2) Has a double bond, not triple
(3) Has a double bond, not triple bond
(4) Is an alkane, it only has single bonds
Therefore the correct answer is (1) C2H2 because it has a triple bond, therefore it is an alkyne.
