Which symbol represents hazardous materials that are non-infectious but chemically reactive?

The correct answer is the corrosive symbol. This symbol is specifically utilized to indicate materials that can chemically react in a hazardous manner, such as those that can corrode or destroy living tissue and other materials. Corrosive substances can cause severe chemical burns and damage to the environment, so it's essential that they are clearly marked to ensure safe handling and storage.

In contrast, other symbols represent different types of hazards. The old radiation symbol warns of radioactive materials, which is not relevant to non-infectious chemically reactive substances. The cytotoxic symbol indicates materials that are toxic to cells, particularly in medical settings, usually referring to hazardous drugs rather than reactive chemicals. The biohazard symbol is used for biological hazards, primarily infectious agents that pose a risk to health, which again does not apply to non-infectious, chemically reactive materials. Thus, the corrosive symbol is the appropriate representation for such hazards.