Silver Mirror

Reference

Tested Demonstrations in Chemistry, 6th ed., Alyea and Dutton, p. 28; Reduction of Silver by Dextrose – Demo # Gen.12

Equipment

• Flasks: 3 squeaky-clean 500 mL round-bottom flasks with rubber stoppers.
• Cleaning Procedure:
  • Use detergent + 3 washes with distilled water.
  • Treat with concentrated nitric acid + 4 washes with distilled water.
  • Store flasks full of distilled water.
• Graduated Cylinders: 4–10 mL

Chemicals

• A: 5.0 g honey in 50 mL distilled water. Add 0.6 g tartaric acid, boil, cool, and add 10 mL ethanol to stabilize. Dilute to 100 mL.
• B: 4.0 g silver nitrate in 50 mL distilled water.
• C: 6.0 g ammonium nitrate in 50 mL distilled water.
• D: 10.0 g sodium hydroxide in 100 mL distilled water.

Procedure

1. Pour 10 mL of solution A into a flask.
2. Mix 5 mL of solution B and 5 mL of solution C, then add to the flask.
3. Quickly pour in 10 mL of solution D.
4. Stopper the flask and vigorously shake.

• IMPORTANT: After a few minutes, pour the flask contents down the sink and wash out the flask to prevent an explosive mixture from forming.

What is Happening

• The silver present initially reacts with ammonia (NH₃) to form Ag(NH₃)₂⁺.
• The dextrose, a sugar present in honey, gently reduces the silver ions to pure silver metal.
• If the reaction occurs too quickly, silver would precipitate in the solution rather than deposit on the walls of the flask.