Final answer:
Chelating agents function by sequestering metal ions, forming complexes that prevent the metals from reacting and causing issues in various applications including water treatment, food preservation, and medical treatments for heavy metal poisoning.
Step-by-step explanation:
The function of a substance containing active chelating agents is accurately described by the statement that it helps in metal ion sequestration. Chelating agents have the ability to bind to metal ions, effectively forming a stable complex that prevents the metals from participating in unwanted reactions such as oxidation or catalysis.
These complexes can remove metals like calcium, magnesium, iron, and copper which, in their ionic form, can cause problems such as making water hard or accelerating the degradation of food products through catalyzed reactions. Substances like EDTA are examples of chelating agents that bind metal ions using multiple donor atoms, making them unavailable for reactions that could lead to spoilage or toxicity. Therefore, these agents are pivotal in water treatment, food preservation, and medical applications, such as treating heavy metal poisoning.