Tollen's Test (Silver Mirror)

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

Visão geral

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.

Participantes

Papel Substância Coeficiente Estado
Produto Water H₂O 1 (l)
Produto Silver Ag 2 (s)
Produto Ammonia NH₃ 4 (aq)

Exemplo do cotidiano

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

Importância industrial

O teste de Tollens é utilizado em química orgânica para identificação de aldeídos. A produção de espelhos de prata por redução química ainda é utilizada para espelhos de alta qualidade.

Propriedades

Tipo
Redox
Reversível
Não
Energia
Exotérmico
ΔH
-135,0 kJ/mol

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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.