What is another chemical used alongside iodine to purify water?

Chlorine Dioxide is a chemical commonly used alongside iodine for water purification. It is an effective disinfectant that can kill bacteria, viruses, and protozoa, making it a reliable choice for treating contaminated water. Chlorine Dioxide works effectively in a wide range of water conditions and is considered to cause less taste and odor compared to other chemicals.

The other options, while they have useful applications in water treatment, do not complement iodine as specifically as Chlorine Dioxide does. Calcium Hypochlorite is primarily used on its own as a chlorine source, while Potassium Permanganate can indeed be used for water treatment but is typically applied in a different context. Ozone is another powerful disinfectant that operates differently and is not usually combined with iodine for purification purposes.