Which statement about ketones is true?

Which statement about ketones is true?

• A. They must be stored at body temperature
• B. They are volatile at any temperature
• C. They cannot evaporate
• D. They can evaporate in cooler temperatures

Answer: (D)

Ketones are volatile organic solvents with measurable vapor pressure at room temperature, so they readily vaporize even when kept cooler than body temperature. Because their vapor pressure is nonzero at typical lab temperatures, evaporation can occur without heating to boiling. For example, acetone boils at about 56°C, yet it evaporates readily at room temperature, illustrating why it can evaporate in cooler temperatures. The idea that they must be stored at body temperature is incorrect, and the notion that they cannot evaporate is false; the blanket statement that they are volatile at any temperature is too absolute, since evaporation depends on temperature and vapor pressure.

Ketones are volatile organic solvents with measurable vapor pressure at room temperature, so they readily vaporize even when kept cooler than body temperature. Because their vapor pressure is nonzero at typical lab temperatures, evaporation can occur without heating to boiling. For example, acetone boils at about 56°C, yet it evaporates readily at room temperature, illustrating why it can evaporate in cooler temperatures. The idea that they must be stored at body temperature is incorrect, and the notion that they cannot evaporate is false; the blanket statement that they are volatile at any temperature is too absolute, since evaporation depends on temperature and vapor pressure.