Nessler's reagent

[nes-lerz]
noun
  1. an aqueous solution of potassium iodide, mercuric chloride, and potassium hydroxide, used as a test for the presence of ammonia.

Origin of Nessler's reagent

First recorded in 1870–75; see origin at nesslerize
Also called Nessler's solution.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018