Silver Nitrate (AgNO3)



Silver Nitrate is commonly     known as Lunar caustic.

 

 Preparation

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.

 

Properties

 

It is colorless crystalline solid soluable 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 decompose forming silver nitrite which on further heating decompose giving silver metal.

2AgNO3                →                  2AgNO2 + O2

AgNO2                    →                  Ag + NO2

 

Precipitation reaction

AgNO3 gives precipitate with halide ion (Cl,  Br  & I  ) and from color of precipitate the halide ion can be identified.

Cl  + AgNO2          →                 AgC + NO3

Curdy white

Br  + AgNO2              →             AgBr + NO3

Pale yellow

I  + AgNO2           →                  AgI + NO3

Yellow ppt

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

Toller’s reagent

 

Uses

 

i. it is used in makingsilver halides used in photography.

ii. It is used in making inks and hair dye’s.

iii. It is used in making silver mirror.

iv. It is used in lab as analytical reagent.