Editing Tollens' reagent (section)

{{short description|Chemical reagent used to distinguish between aldehydes and ketones}}
{{Use dmy dates|date=November 2022}}
[[File:Tollens.JPG|thumb|upright=1.0|Tollens' test for aldehyde: left side positive (silver mirror), right side negative]]
[[File:Diamminesilver(I)-3D-balls.png|thumb|right|200px|[[Ball-and-stick model]] of the diamminesilver(I) complex]]

'''Tollens' reagent''' (chemical formula <chem>Ag(NH3)2OH</chem>) is a chemical [[reagent]] used to distinguish between [[aldehyde]]s and [[ketone]]s along with some [[alpha-hydroxy ketone]]s which can [[tautomerize]] into aldehydes. The reagent consists of a solution of [[silver nitrate]], [[ammonium hydroxide]] and some [[sodium hydroxide]] (to maintain a basic [[pH]] of the reagent solution). It was named after its discoverer, the German chemist [[Bernhard Tollens]].<ref>{{cite journal|last1=Tollens|first1=B.|title=Ueber ammon-alkalische Silberlösung als Reagens auf Aldehyd|journal=Berichte der Deutschen Chemischen Gesellschaft|date=1882|volume=15|issue=2|pages=1635–1639|url=https://zenodo.org/record/1910987|trans-title=On an ammonical alkaline silver solution as a reagent for aldehydes|language=de|doi=10.1002/cber.18820150243}}</ref> A positive test with Tollens' reagent is indicated by the precipitation of elemental silver, often producing a characteristic "[[Silvering|silver mirror]]" on the inner surface of the reaction vessel.