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Tollens' Test for Aldehydes


  • The greatest hazard is formation of silver fulminate. To avoid formation of silver fulminate dispose of the Tollens' test immediately after performing the experiment.
  • Silver nitrate stains fingers.
  • Potassium hydroxide is caustic and toxic.
  • Ammonia is caustic and has irritating vapors

Chemicals and Solutions

  • Tollens' Solution A (dilute sugar/acid)
  • Tollens' Solution B (potassium hydroxide, silver nitrate, ammonia)


  1. 500 ml test tube and rack.
  2. Add 6 mL of Tollens' Solution A to the large test tube.
  3. Pour in 400 mL of Tollens' Solution B. Within a minute the tube should darken and begin to form a silver mirror.