Which chemical has the lowest odor threshold among the following: Hexane, Dichloromethane, Ethyl acetate, Methanol?

• A. Ethyl acetate
• B. Hexane
• C. Dichloromethane
• D. Methanol

Answer: (A)

Odor threshold is the smallest amount of a substance in air that can be detected by the sense of smell. A substance with a low odor threshold is perceived at very low concentrations, which often occurs when the compound is both volatile and has a potent, distinctive odor.

Ethyl acetate fits this idea well. It has a fruity, easily recognizable odor and evaporates readily, so it reaches the nose quickly even when present in small amounts. That combination makes its odor detectable at lower concentrations than the others listed. Hexane tends to smell faint and is harder to detect at low levels. Methanol has a milder odor, not as easily detected at tiny concentrations. Dichloromethane has a sharp odor, but its threshold is typically higher than that of ethyl acetate. So the substance with the lowest odor threshold among these is ethyl acetate.