Definition and Uses :
Silver nitrate can be prepared by reacting silver, such as silver ingots or silver foil, with nitric acid, resulting in silver nitrate, water, and nitrogen oxides. The reaction by-products depend on the concentration of nitric acid used.
3 Ag + 4 HNO 3 (cold and dilute) → 3 AgNO 3 + 2 H 2 O + NONE
Ag + 2 HNO 3 (hot and concentrated) → AgNO 3 + H 2 O + NO 2
This is done under a fume hood due to the toxic nitrogen oxide(s) evolved during the reaction.
A typical reaction with silver nitrate involves suspending a copper rod in a silver nitrate solution and leaving it for several hours. Silver nitrate reacts with copper to form hairy silver metal crystals and a blue copper nitrate solution:
2 iodine 3 + Cu → Cu (NO 3 ) 2 + 2 Ag
Silver nitrate decomposes when heated:
2 iodine 3 2 Ag (s) + → (I) O 2 (g) + 2 NO 2 (g)
Most metal nitrates thermally decompose to the corresponding oxides, but silver oxide decomposes at a lower temperature than silver nitrate, so decomposition of silver nitrate yields elemental silver instead.