Sentence:  The thermal exchange of <WSD>chlorine</WSD> between * * f and liquid * * f is readily measurable at temperatures in the range of 180 ` and above . 
Meaning of the word marked with <WSD> tags:  a common nonmetallic element belonging to the halogens; best known as a heavy yellow irritating toxic gas; used to purify water and as a bleaching agent and disinfectant; occurs naturally only as a salt (as in sea water)