Scientists and industry professionals would go into detailed descriptions of the element’s chemical construction, such as its periodic symbol Cl and atomic number 17 and its uses across a huge number of industries. The average homeowner and consumer would mention its use in cleaning agents such as bleach and come across it at their local swimming pool and its most common compound, sodium chloride, at the dinner table.

The scientific or industrial answer to ‘what is chlorine?’ involves describing why chlorine, along with other elements in the halogen group such as bromine and iodine, can be used to disinfect water and surfaces so that they can be safely used by humans. Because chlorine is extremely reactive with a variety of other substances, it can be used to bond with harmful pathogens, such as viruses, parasites and fungi, to render them harmless to humans who come in contact with them. However, for use in cleaning agents and in the swimming pool chlorine must be used with caution, as its high reactivity can also cause it to harm the human body in a variety of ways.

For owners of home pools who need to disinfect their water and ensure it stays clean, the question of ‘what is chlorine?’ becomes simple. Buckets of the granulated chemical, such as hth chlorine, are ideal for sanitising an entire pool of water. Available in several distinct varieties, and in bucket sizes of either 1kg or 25kg, stabilised chlorine granules act by releasing chlorine throughout the body of water so that it may bond with the pathogens there, neutralising their harmfulness to humans.

Chlorine tablets that test for levels of the chemical in water are key to ensuring there isn’t too much, which would be harmful to swimmers, or too little, which would not effectively neutralise germs and parasites.