“Silver mirror” experiment
How to make a mirror from 2 solutions
How can you make a mirror from two solutions in 20 minutes? Here’s an experiment to make a mirror surface based on the qualitative “Silver mirror reaction”.
Safety precautions
Wear gloves and protective glasses and work in a well-ventilated room when conducting the experiment.
Reagents and equipment:
- silver nitrate 5 g/l;
- glucose 5 g/l;
- ammonia solution 10%;
- sodium hydroxide 5 g/l;
- distilled water 200 ml;
- Petri dish;
- beakers.
Step-by-step instructions
To prepare the silvery solution, namely the ammonia solution of silver oxide (Tollens’ reagent), mix the solution of silver nitrate and a few milliliters of sodium hydroxide. A brown sediment of silver oxide forms. Then add the ammonia until the sediment dissolves completely. It’s important to remember that an abundance of ammonia can affect the quality off the covering and the speed at which the silver settles.
Into a Petri dish, pour the ammonia solution of silver oxide (or Tollens’ reagent) and the glucose solution. After a while the dish will start to become covered with a thin layer of silver. Rinse the residue of the reactive mixture from the Petri dish with water.
Processes description
Metallic coatings are widely used in industry, in particular coatings of silver. The technology is based on the well-known “silver mirror” reaction, i.e. the reduction of silver ions from the ammonia solution of silver oxide by any substance from the aldehyde group, for example glucose. The reduced silver settles on the surface of the Petri dish in the form of a mirror coating.
НОСН₂(СНОН)₄HС=O (glucose) + 2[Ag(NH₃)₂]OH => НОСН₂(CHОН)₄СООH + 2Ag +4NH₃ + 2H₂O
