Silver Nitrate
Properties
| State | Solid (white crystalline) |
| Color | White (darkens on exposure to light) |
| Solubility | Highly soluble in water (2560 g/L at 20°C) |
| Melting Point | 212°C |
| Boiling Point | 444°C (decomposes) |
About Silver Nitrate
Silver nitrate is the workhorse soluble silver salt — almost every other silver compound you encounter in a lab or factory traces back to AgNO3 dissolved in something. With a molar mass of 169.872 g/mol and a solubility north of 2,500 g/L at room temperature, it dumps Ag+ into solution faster than just about any other heavy-metal salt, which is exactly why analytical chemists reach for it. Drop a few drops into an unknown halide solution and the precipitate tells you what you have: white curdy AgCl, pale cream AgBr, yellow AgI. The Mohr titration for chloride uses it with a chromate indicator; the Volhard back-titration uses it with thiocyanate. In organic synthesis, AgNO3-impregnated silica plates separate olefins and aromatics by argentation chromatography because Ag+ binds π-systems. The stains on your fingers if you skip gloves are not the nitrate — they are colloidal silver metal generated when light reduces AgCl that formed from your skin's chloride.
Where you'll encounter it
If you've ever run Tollens' test for an aldehyde and watched a silver mirror plate the inside of a clean test tube, that's AgNO3 plus ammonia plus a little NaOH doing the work. In a darkroom, AgNO3 was the starting point for emulsion chemistry — react it with KBr and gelatin and you get the silver bromide microcrystals that became film and printing paper. Newborn nurseries used to put a 1% solution into babies' eyes (Credé's prophylaxis) to prevent gonococcal conjunctivitis before erythromycin ointment took over. In modern wound care, silver-impregnated dressings like Acticoat slow-release Ag+ to suppress MRSA and Pseudomonas in chronic burns. Cauterizing a stubborn nosebleed in an ENT clinic? That woody applicator stick tipped with fused AgNO3 is lunar caustic — same compound the alchemists named it.
Common Uses
- Halide ion identification by precipitation in qualitative inorganic analysis
- Mohr and Volhard titrations for chloride and bromide quantification
- Tollens' reagent for distinguishing aldehydes from ketones
- Silver halide emulsion synthesis for film, paper, and X-ray plates
- Argentation chromatography on AgNO3-silica plates for olefin separation
- Cauterization sticks for granulation tissue and minor nosebleeds
- Antimicrobial loading of burn dressings and indwelling catheter coatings
- Starting material for silver electroplating bath formulation
Safety Information
Corrosive oxidizer. GHS: H272 (intensifies fire), H314 (severe skin and eye burns), H410 (very toxic to aquatic life with long-lasting effects). OSHA PEL for soluble silver compounds is 0.01 mg/m³ as Ag, 8-hour TWA. Skin contact produces black argyric stains within hours of light exposure that take weeks to wear off. Chronic systemic exposure causes argyria — irreversible blue-gray skin discoloration from subdermal silver deposition. Wear nitrile gloves (latex is permeable), splash goggles, and keep away from organics, alcohols, and ammonia (potentially explosive silver fulminate or silver nitride can form). Spill cleanup: precipitate as AgCl with brine before disposal as silver-bearing waste.
This safety summary is for educational reference only and may not be complete. It is not a substitute for Safety Data Sheets (SDS), medical advice, or professional chemical safety guidance. Always consult appropriate SDS and qualified professionals before handling chemicals.