Final answer:
Converting an alkene to an alkane requires a hydrogenation reaction, where hydrogen is added across the alkene's double bond in the presence of a platinum catalyst. Alternately, alkenes can be hydrated to form alcohols with a strong acid catalyst, and then potentially dehydrated and hydrogenated to form an alkane.
Step-by-step explanation:
To convert an alkene to an alkane, a process called hydrogenation is used. In this reaction, molecular hydrogen (H2) is added across the double bond of the alkene, resulting in an alkane with the same carbon skeleton as the original alkene. This reaction generally requires a catalyst, such as platinum, to proceed.
An alkene can also react with water in a process called hydration, where the alkene is converted into an alcohol. This transformation often necessitates a strong acid catalyst like sulfuric acid (H2SO4). The hydration of ethene, for example, will produce ethanol. While this does not directly produce an alkane, further reaction steps like dehydration can revert the alcohol to an alkene, which could then be hydrogenated to form an alkane.
For purposes of identification and testing, alkenes can undergo a reaction known as halogenation, where halogens like bromine (Br2) are added across the double bond. Bromine water turns colorless in the presence of alkenes, indicating that the halogenation is taking place. However, this reaction does not produce alkanes but is useful for confirming the presence of double bonds in alkenes.