Tollen’s Test: Procedure

The procedure for Tollen’s test is:

1. Put 1 mL of silver nitrate in test tube
2. Add 1 drop of sodium hydroxide solution to the test tube
3. Shake the test tube.
4. Observe dark brown precipitate
5. Add ammonium hydroxide dropwise to the test tube until the solution becomes colourless again
6. Add 2-3 drops of the sample
7. Pick up the test tube with the tongs/holder
8. Put the test tube in the water bath for 5 minutes
9. Using the tongs, take test tube out of water bath and put in tube rack
10. Observe formation of silver mirror.
11. Add dilute nitric acid and drain off the solution with an excess of water to prevent explosive silver nitride forming.

Figure 1 - Tollen's test procedure for detecting the presence of reducing sugars in a sample.