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In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.

In the presence of this compound, Nessler's reagent turns yellow. A solution of sodium in this compound is used in the Birch reduction. Its liquid form notably has a specific heat capacity higher than that of water. The reaction used to synthesize it most commonly employs an iron catalyst. It is oxidated in the Ostwald process for producing nitric acid, and this compound itself is produced by the Haber-Bosch process. For 10 points, name this trigonal pyramidal compound with formula NH3.
Output:
Science