IPA: /ˈtɒlɪdiːn/
KK: /tɑːlɪdaɪn/
A type of chemical compound that is derived from toluene and has several isomers. It is used in testing for gold and chlorine in water, and also as an intermediate in dye production.
The chemist used tolidine as a reagent to test the water for chlorine.
Tolidine is derived from the combination of 'tol' (from toluene, a chemical compound) and 'idine' (a suffix used in chemistry to denote a derivative of a compound). The word refers to a specific type of chemical compound related to toluene.
Think of 'tol' as relating to toluene, which helps you remember that tolidine is a derivative of that chemical.