What are the names of the first four members of the homologous series of alkenes?

The first four members of the homologous series of alkenes are correctly identified as ethene, propene, butene, and pentene. Alkenes are characterized by having at least one carbon-carbon double bond and generally follow the formula CnH2n, where n represents the number of carbon atoms.

Starting with ethene, which has two carbon atoms (C2), as the smallest alkene, it is followed by propene (C3), then butene (C4), and finally pentene (C5). Each subsequent member of the series increases the carbon chain length by one carbon atom, which in turn increases the hydrogen count according to the alkene formula.

In comparison, the other options denote different types of compounds or series. The second choice lists alcohols, indicated by the presence of the hydroxyl (-OH) group, while the third and fourth choices refer to alkanes, which are saturated hydrocarbons characterized by single bonds only. Thus, these alternatives do not meet the criteria for alkenes, making the selection of the first four members of the alkene series as ethene, propene, butene, and pentene the correct one.