Final answer:
The correct answer for the conjugate acid of ethanol should be ethyl cation (CH3CH2OH2+), but this is not listed among the options. None of the given choices correspond to a conjugate acid of ethanol.
Step-by-step explanation:
The conjugate acid of ethanol is the species that results from the acceptance of a proton (H+) by ethanol. When ethanol (CH3CH2OH) acts as a base and gains a proton, it transforms into ethyl cation (CH3CH2OH2+). However, this is not one of the presented options. Among the given options, ethanoic acid, or acetic acid (CH3COOH), is another compound entirely and it's not the conjugate acid of ethanol. To clarify, the conjugate acid is typically the same molecule with an additional proton, and none of the other options provided (ethanol, ethylene, or ethylamine) represent a protonated form of ethanol.
Therefore, it may be a trick question or there could be a misunderstanding within the given choices. The correct answer to the question, "Which one of the following is the conjugate acid of ethanol?" should technically be "ethyl cation (CH3CH2OH2+)", but since it is not listed, the question appears unanswerable based on the provided options.