What is the chemical equation for the dehydration of ethanol?

The dehydration of ethanol is a reaction in which ethanol (C₂H₅OH) loses a water molecule (H₂O) to form ethene (C₂H₄). This process is an elimination reaction, common in organic chemistry, where a smaller molecule—water in this case—is removed, resulting in the formation of a double bond between the carbon atoms in the ethene.

In the correct equation, you see that ethanol is transforming directly into ethene and water, illustrating the nature of the reaction. It succinctly captures the essence of dehydration: two hydrogen atoms and one oxygen atom are no longer part of the product, resulting in the formation of a double bond between the carbon atoms, characteristic of alkenes like ethene.

The other choices don't accurately represent the dehydration reaction. For instance, involving oxygen in the reaction or suggesting the formation of carbon dioxide indicates a different process or reaction mechanism that does not occur during the simple elimination of water from ethanol. By focusing solely on the conversion of ethanol into ethene and water, the correct option appropriately describes the fundamental aspects of this dehydration reaction.