What characteristic defines chemical incompatibility?

Chemical incompatibility is characterized by a change in color, gas, or the formation of new substances when two or more chemicals are mixed together. This indicates that a chemical reaction is taking place, which can result in the creation of unexpected products that may not perform as intended. Such reactions can compromise the efficacy of the pesticide or create harmful byproducts.

When discussing the other options, a failure to mix uniformly refers to physical incompatibility, where the components do not blend well, leading to separation without necessarily indicating a chemical reaction. The consistency of the pesticide mixture pertains to how well the ingredients retain their intended characteristics throughout the mixing process, which does not imply any chemical changes. Lastly, the effectiveness of the pesticide over time is more about the stability and long-term performance of the pesticide rather than describing or identifying chemical incompatibility itself.