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Chemistry LibreTexts

Silver Nitrate

Silver nitrate, AgNO3, is the least expensive silver salt and is relatively stable to light. It easily dissolves in water (2150 g/L at 20 °C). As the nitrate can be easily replaced by other ligands AgNO3 is a versatile starting point for the synthesis of other silver compounds.

Silver nitrate can be prepared by dissolving silver in with nitric acid:

3 Ag + 4 HNO3 3 AgNO3 + NO + 2 H2O

When a sheet of copper is put into a silver nitrate solution, the silver nitrate reacts with copper to form hairlike crystals of metallic silver and a blue solution of copper nitrate:

2 AgNO3 + Cu Cu(NO3)2 + 2 Ag

AgNO3 reacts with solutions of halide ions to give a precipitate of AgX (X = Cl, Br, I), which are used in photographic films.

When heated, silver nitrate decomposes into metallic silver, oxygen and nitrogen oxide:

2 AgNO3 2 Ag + O2 + 2 NO2

Silver salts have antimicrobial properties and are commonly used to disinfect drinking water. When diluted silver nitrate is braught into contact with skin, the skin becomes brown/black after a short time due to elementary silver which is introduced into the skin according to the following reaction:

AgNO3 + H (from the skin) Ag + HNO3

Concentrated solutions of AgNO3 will cause burns due to the same reaction.