Silver Nitrate is commonly known as Lunar caustic.
AgNO3 is prepared by dissolving silver metal in dil HNO3. The silver nitrate solution of crystallization gives colorless crystal of AgNO3.
3Ag + 4HNO3 → 3AgNO3 + NO + 2H2O.
- It is colorless crystalline solid soluble in water.
- It is highly sensitive to light and when kept in contact with skins it leaves a permanent dark stain.
Action of heat
When silver nitrate is heated first it decomposes forming silver nitrite which on further heating decompose giving silver metal.
2AgNO3 → 2AgNO2 + O2
AgNO2 → Ag + NO2
AgNO3 gives precipitate with halide ion (Cl, Br & I ) and from color of precipitate the halide ion can be identified.
Cl + AgNO2 → AgC + NO3
Br + AgNO2 → AgBr + NO3
I + AgNO2 → AgI + NO3
Ammonical Silver Nitrate [Tollen’s reagent] is used to detect reducing groups in organic compounds like aldetyde. The reducing agent reduces tollen’s reagent to metallic silver which deposits in test-tube forming silver mirror.
Ag2O + HCHO → 2Ag + HCOOH
- It is used in making silver halides used in photography.
- It is used in making inks and hair dye’s.
- It is used in making silver mirror.
- It is used in lab as analytical reagent.