What is a fume produced from volatilized solids that condenses in cool air called?

The correct answer is vapor. Vapor refers to the gaseous state of a substance that is normally a liquid or solid at room temperature. When solids volatilize, they turn into a gas and can subsequently condense back into tiny particles or droplets when cooled in the air. This process of transitioning from solid to gas and then condensing is what characterizes vapor.

In contrast, gas is a general term that describes a state of matter, but it does not specifically address the process of condensation from solid to gas and back. Aerosol refers to a mixture of fine solid particles or liquid droplets suspended in air, but it generally involves both liquids and solids rather than just the vaporization of solids. Mist typically refers to tiny liquid droplets suspended in the air, often resulting from condensation or evaporation situations, but does not capture the aspect of volatilization from solids specifically.

Thus, vapor is the most accurate term for describing the fume produced from volatilized solids that condenses in cool air.