Recreational Vehicle (RV) Technician Practice Test

Which chemical is responsible for giving propane its odor?

1. Ethel mercaptan

2. Propylene glycol

3. Methyl ethyl ketone

4. Butane

The correct answer is: Ethel mercaptan

The chemical responsible for giving propane its distinct odor is ethyl mercaptan. Propane, being a colorless and odorless gas in its natural state, can be dangerous because leaks are difficult to detect without an added scent. Ethyl mercaptan has a strong and unpleasant odor that can easily alert users to the presence of propane gas, which is crucial for safety in residential and recreational applications. The addition of this chemical is a standard practice in the propane industry to help prevent accidents and ensure that leaks are noticed quickly. Other substances listed, like propylene glycol, methyl ethyl ketone, and butane, do not serve the same purpose and are not used as odorants in propane. Propylene glycol is commonly used in food and pharmaceutical applications, methyl ethyl ketone is a solvent, and butane is a different type of hydrocarbon used as a fuel. Therefore, ethyl mercaptan is the correct answer for providing the characteristic odor that identifies propane.