Tollen's Test (Silver Mirror)

RCHO + 2Ag(NH3)2+ + 2OH− → RCOO− + 2Ag + 4NH3 + H2O

Übersicht

Tollens' reagent (silver-ammonia complex) is reduced to metallic silver by aldehydes, producing a silver mirror on the test tube walls. The aldehyde is oxidized to a carboxylate. This test distinguishes aldehydes from ketones, as ketones cannot be easily oxidized. It was historically used for mirror manufacturing.

Teilnehmer

Rolle Substanz Koeffizient Zustand
Produkt Water H₂O 1 (l)
Produkt Silver Ag 2 (s)
Produkt Ammonia NH₃ 4 (aq)

Alltägliches Beispiel

The silver mirror test creates a beautiful reflective coating on glass, and this chemistry was actually used to make mirrors commercially.

Industrielle Bedeutung

Tollens' test is used in organic chemistry for aldehyde identification. Silver mirror manufacturing by chemical reduction is still used for high-quality mirrors.

Eigenschaften

Typ
Redox
Reversibel
Nein
Energie
Exotherm
ΔH
-135,0 kJ/mol

Verwandte Reaktionen

Iron(II) to Iron(III) Oxidation by Oxygen Bleaching with Sodium Hypochlorite Copper Reduction of Silver Ion Aqua Regia Dissolving Gold Cerium(IV) Reduction by Iron(II) Copper Oxidation by Nitric Acid Hypochlorite Oxidation of Hydrogen Peroxide Hydrogen Peroxide as Oxidizing Agent (Acidic) Hydrogen Peroxide Disproportionation Displacement of Hydrogen from Acid by Magnesium

Frequently Asked Questions

What is the equation for Tollen's Test (Silver Mirror)?
The balanced equation is: RCHO + 2Ag(NH₃)₂⁺ + 2OH⁻ → RCOO⁻ + 2Ag + 4NH₃ + H₂O.
What type of reaction is Tollen's Test (Silver Mirror)?
Tollen's Test (Silver Mirror) is a redox reaction.
Is Tollen's Test (Silver Mirror) exothermic or endothermic?
Tollen's Test (Silver Mirror) is exothermic (releases energy). The enthalpy change (ΔH) is -135.0 kJ/mol.