Which of the following chemical properties can categorize a substance as hazardous?

A substance can be categorized as hazardous based on its toxicity, which refers to its ability to cause harm to living organisms through chemical interactions. Toxic substances can induce adverse effects on health, such as poisoning, irritation, or long-term damage to organs, making them a significant concern in the context of hazards.

While solubility, color, and flammability are all important properties to consider, they do not inherently define a substance as hazardous without additional context. For example, solubility can affect how a substance behaves in the environment but does not directly indicate whether it is harmful. Color is primarily a physical characteristic and does not reflect the health risks associated with a chemical. Flammability does suggest some level of hazard since a flammable substance can pose fire risks, but it does not encompass the range of toxic effects that a substance may have when ingested or absorbed by living organisms. Therefore, toxicity is the most definitive indicator of a substance's potential to be hazardous.