Active chlorine is a term commonly used in chemistry to describe the amount of chlorine present in a substance that is effective in chemical reactions. However, there are many alternative terms and synonyms which can be used to describe active chlorine. Some of these include available chlorine, residual chlorine, free chlorine, and chloramine. Each of these terms refers to the amount of chlorine present in a particular substance, and is used to help scientists and researchers better understand the chemical properties and reactions of chlorine. Understanding the different terms and synonyms used for active chlorine is important for anyone involved in the field of chemistry.