A volatile substance is characterized by which of the following properties?

A volatile substance is primarily characterized by its ability to evaporate at low temperatures. This property is fundamental to understanding volatility; such substances have a low boiling point, which allows them to transition from liquid to gas relatively easily when exposed to air or heat. This characteristic is significant in various fields, including environmental science and engineering, because volatile substances can impact air quality and the behavior of certain industrial processes.

The incorrect options can be explained in terms of their characteristics not aligning with the definition of volatility. High viscosity typically refers to a thick or sticky consistency, which is not a trait associated with volatile substances. Highly acidic substances pertain to their pH level but do not indicate volatility. Lastly, being solid at room temperature implies that the substance does not readily evaporate, which contradicts the idea of being volatile. Thus, the ability to evaporate at low temperatures distinctly defines a volatile substance.