What is a volatile compound?

What is a volatile compound?

• A. A large molecule with low vapor pressure
• B. A small molecule with high tendency to evaporate
• C. A stable ionic compound
• D. A polymer

Answer: (B)

Volatility describes how readily a substance becomes a gas. This is tied to vapor pressure—the higher the vapor pressure at a given temperature, the more volatile the substance. Small molecules typically have weaker intermolecular forces or lower boiling points, so they evaporate more easily. That’s why a small molecule with a high tendency to evaporate best fits the idea of a volatile compound. The other descriptions don’t fit because a large molecule with low vapor pressure tends to stay in the liquid or solid phase, an ionic compound forms a stable lattice and isn’t volatile under normal conditions, and polymers are generally bulky and have low volatility.

Volatility describes how readily a substance becomes a gas. This is tied to vapor pressure—the higher the vapor pressure at a given temperature, the more volatile the substance. Small molecules typically have weaker intermolecular forces or lower boiling points, so they evaporate more easily. That’s why a small molecule with a high tendency to evaporate best fits the idea of a volatile compound.

The other descriptions don’t fit because a large molecule with low vapor pressure tends to stay in the liquid or solid phase, an ionic compound forms a stable lattice and isn’t volatile under normal conditions, and polymers are generally bulky and have low volatility.