What is the IUPAC name for C4H6?

The correct IUPAC name for C4H6 is butyne. To understand why this is the case, it's essential to analyze the structure of the compound based on the molecular formula.

C4H6 indicates that there are four carbon atoms and six hydrogen atoms in the molecule. One important aspect of the nomenclature in organic chemistry is to identify whether the compound is saturated or unsaturated.

Saturated hydrocarbons, which have only single bonds between carbons, would have the general formula CnH2n+2. For four carbon atoms (n=4), this would mean C4H10 is a saturated hydrocarbon, which is butane. However, since C4H6 has fewer hydrogen atoms than butane, it must contain multiple bonds.

For unsaturated hydrocarbons, we can have alkenes (with double bonds) or alkynes (with triple bonds). The general formula for alkenes is CnH2n, which means C4H8 for n=4, while for alkynes, the formula is CnH2n-2, which results in C4H6 when n=4.

Therefore, since the molecular formula C4H6 fits the pattern of an