The aldehydes in reducing sugars will reduce silver ion from Tollen's reagent to metallic silver, leaving a reflective mirror on the inside of a flask.
RCHO + 2Ag(NH3)2OH → 2Ag(s) + RCOONH4+ + NH3 + H2O
To Conduct Demonstration:
Safety and Disposal
Silver nitrate will stain skin and clothing on contact. Gloves should be worn. Avoid breathing ammonia vapors.
Use concentrated HNO3 to dissolve silver coating on flask.
D.J. Pasto and C.R. Johnson, Laboratory Text for Organic Chemistry, p 409,1979.
Margaret Asirvatham, Spring 1988; Tom Cech, Fall 1995.