2. Silver Nitrate
• Silver nitrate is an inorganic compound with chemical
formula AgNO3. This compound is a versatile precursor to
many other silver compounds, such as those used
in photography.
• It was once called lunar caustic because silver was
called luna by the ancient alchemists, who believed that silver
was associated with the moon.
• In solid silver nitrate, the silver ions are three-coordinated in a
trigonal planar arrangement.
3. Physical Properties
• .Mol. Wt. 169.87 g·mol−1
Appearance colorless solid, rhombic crystals,
having bitter, caustic metallic taste
Odor Odorless
Density 4.35 g/cm
3
(24 °C)
Melting point 209.7 °C (409.5 °F; 482.8 K)
Boiling point
Solubility
440 °C (824 °F; 713 K)
decomposes
1gm/0.4ml in water, 30ml in alcohol at
25C , slightly soluble in ether.
4. Chemical Properties
• A typical reaction with silver nitrate is to suspend a rod
of copper in a solution of silver nitrate and leave it for a few
hours. The silver nitrate reacts with copper to form hair like
crystals of silver metal and a blue solution of copper nitrate:
2 AgNO3 + Cu → Cu(NO3)2 + 2 Ag
5. Cont…
• Silver nitrate decomposes when heated:
• 2 AgNO3(l) → 2 Ag(s) + O2(g) + 2 NO2(g)Qualitatively,
decomposition is negligible below the melting point, but
becomes appreciable around 250 °C and totally decompose at
440 °C.
• Treatment of silver nitrate with base gives dark grey silver
oxide
• 2 AgNO3 + 2 NaOH → Ag2O + 2 NaNO3 + H2O
6. Synthesis
• Silver nitrate can be prepared by reacting silver, such as a
silver bullion or silver foil, with nitric acid, resulting in silver
nitrate, water, and oxides of nitrogen. Reaction by products
depend upon the concentration of nitric acid used.
• 3 Ag + 4 HNO3 (cold and diluted) → 3 AgNO3 + 2 H2O + NO
• Ag + 2 HNO3 (hot and concentrated) → AgNO3 + H2O + NO2
• This is performed under a fume hood because of toxic
nitrogen oxide(s) evolved during the reaction.
7. Cont…
• Silver nitrate can be prepare with nitric acid. About 3 parts of
metallic silver are mixed with 10 parts of 25% nitric acid.
• The mixture is gently warmed , as the silver is dissolve, the
solution is filtered and evaporated to dryness.
3AG + 4HNO3 3AgNO3 + 2H2O + NO
8. Applications
• Silver nitrate in the liquid form is diluted
with water, This solution is used as a mild
antiseptic in medical settings. Basically
silver ion can precipitate proteins so this
gives germicidal activity.
• A 1 to 2 percent solution is effective
against gonococcal bacteria, which cause
gonorrhea. Starting in 1881, doctors
administered this silver nitrate solution
directly into the eyes of newborn babies
born to gonorrhea-infected mothers to
prevent the babies from developing
blindness due to the infection.
9. Cont…
• Used in stick form, silver nitrate is used for the treatment and
removal of warts. It is also used for cauterizing wounds and
lesions to stop bleeding and prevent infection. The stick is
ideally moistened with distilled water and placed against the
wound, wart or lesion for a period of one to two minutes,
once daily.
10. Cont…
• Beyond its many medical uses, silver nitrate is used in
laboratories to test for the presence of substances such as
chlorine, hydroxide and iodide ions.
• In manufacturing, it is used in hair dyes and permanent fabric
markers.
• It is also use in making inks.
11. Forms of Medication
• Topical Solutions ( 0.5 -50%)
• Topical compounding powder
• Topical ointment
• Ophthalmic solutions
