Potassium permanganate (${\text{KMnO}}_4$) is used to purify drinking water because it is an effective ____________ agent.

Potassium permanganate (${\text{KMnO}}_4$) is a powerful oxidizing agent. When added to well water or raw water, it oxidizes dissolved iron, manganese, and hydrogen sulfide into insoluble solid particles, which can then be easily filtered out. It also inactivates many microorganisms and organic matter through oxidation mechanisms.