Final answer:
Upon reduction with H2 and Lindlar's catalyst, the symmetrical alkyne C6H10 forms the alkene 3-hexene. This conclusion is based on ozonolysis yielding a single type of aldehyde, implying a symmetrical structure of the original alkyne.
Step-by-step explanation:
The alkyne with molecular formula C6H10 upon reduction with H2 and Lindlar's catalyst followed by ozonolysis yielding only one aldehyde product suggests that the alkyne had to be symmetrical. Therefore, the starting alkyne must have been 3-hexyne since its reduction would lead to the alkene, 3-hexene. Upon ozonolysis of 3-hexene, only one type of aldehyde, propanal, would be formed, supporting the evidence provided by the single aldehyde product.
When naming the resulting alkene from the reduction of the original alkyne by IUPAC rules, the longest carbon chain is identified and numbered so that the double bond has the lowest possible number. Since the double bond starts on the third carbon atom in the chain of six carbon atoms, the IUPAC name of the alkene formed is 3-hexene.