Which of the following describes the conversion of ethanol to ethene?

• A. Warm the ethanol.
• B. Pass the ethanol vapour over aluminium oxide (catalyst).
• C. Ethene is collected by displacement of water.
• D. All of the above.

Answer: (D)

The conversion ethanol to ethene is a dehydration reaction, where water is removed from the alcohol to form an alkene (C2H5OH → C2H4 + H2O). To drive this reaction you need to supply energy, so heating the ethanol provides the necessary temperature for dehydration to occur effectively. Passing the ethanol vapour over aluminium oxide acts as a catalyst that speeds up the elimination of water, making the formation of ethene more likely at a practical temperature. Once ethene is formed, it is a gas that is not very soluble in water, so it can be collected by displacement of water. Putting these steps together shows why all of them describe a typical method for producing ethene from ethanol, so all of the above is the best answer.