Properties of Silver Nitrate or Lunar Caustic

Physical Properties Properties of Silver nitrate (AgNO₃)

Physical Properties

1. It is soluble in water.
2. Its aqueous solution may decompose on exposure to light.

Chemical Properties

• Action of Heat

On heating AgNO₃ decomposes in two stages

2AgNO₃ –723 K→ 2AgNO₂ + O₂  (Silver nitrite)

AgNO₂ — 980 K→ Ag + NO₂

• With NaCl

AgNO₃ gives white precipitate of AgCl with soluble ionic chlorides.

AgNO₃ + NaCl → AgCl↓ + NaNO₃

• Silver nitrate is strongly caustic and oxidizing in nature.

• With KBr & KI

AgNO₃ gives pale yellow precipitate of AgBr with bromides and yellow AgI with iodides.

AgNO₃ + KBr → AgBr + KNO₃ (Yellow ppt)

AgNO₃ + KI → AgI + KNO₃ (Yellow ppt)

• Action with organic compounds

Ammoniacal silver nitrate (Tollen’s reagent) is reduced to silver mirror by compounds like formic acid, formaldehyde or glucose:

2AgNO₃ + 2NH₄OH → Ag₂O + 2NH₄NO₃ + H₂O

Ag₂O + HCOOH → 2Ag↓ + H₂O + CO₂