This type of oil contains fewer heavy molecules and more intermediates than black oils.

• A. Heavy oil
• B. Medium oil
• C. Light crude
• D. Volatile oil

Answer: (D)

Volatility in oil is tied to how light or heavy the hydrocarbon molecules are. Oils with fewer heavy, long-chain molecules have more of the mid-range, intermediate-size hydrocarbons that sit between the very light gases and the heavy, viscous fractions. That’s what makes the oil more volatile and gives it a higher proportion of intermediates compared with black oils, which are dominated by heavy, long-chain molecules and are less prone to vaporize. So the description fits volatile oil best.