Which of the following is NOT a method to purify water?

Filtration is a widely recognized method for purifying water by physically removing particles, sediments, and certain microorganisms from the water. It involves passing water through a filter designed to trap these contaminants. This method is effective for improving water clarity and safety for consumption.

Boiling, iodine tablets, and calcium hypochlorite (if you meant calcium hypochlorite rather than "calcium hydro chloride") are all established methods for purifying water, as they kill pathogens and help make water safer to drink. Boiling water kills bacteria, viruses, and parasites through high temperatures. Iodine tablets release iodine into water, effectively disinfecting it by targeting microorganisms. Similarly, calcium hypochlorite is a chlorine compound that is used to treat water by desensitizing and killing harmful microorganisms.

While considering the effectiveness of each method, it's vital to recognize that filtration is a legitimate and common approach to water purification, contrary to the conclusion drawn from the options.