Silver Nitrate (AgNO₃) — Properties, Uses & Safety

Overview

Silver nitrate (AgNO3) is an inorganic salt with a molar mass of 169.87 g/mol, consisting of silver cations (Ag+) and nitrate anions (NO3-). At standard conditions, it appears as a colorless crystalline solid that is highly soluble in water. One of silver nitrate's most distinctive properties is its ability to stain skin, clothing, and other organic materials dark brown or black upon exposure to light — a photochemical reduction of Ag+ to metallic silver that formed the basis of traditional photography. Silver nitrate carries significant GHS hazard codes: H271 (may cause fire or explosion as a strong oxidizer), H290 (may be corrosive to metals), H314 (causes severe skin burns and eye damage), and H410 (very toxic to aquatic life with long-lasting effects). Careful handling with gloves and eye protection is essential. Silver nitrate has been used for centuries as an antiseptic and cauterizing agent in medicine. It is applied to wounds and used in silver nitrate sticks to treat nosebleeds and remove warts. In chemistry laboratories, AgNO3 is indispensable for qualitative analysis — the silver halide precipitation test identifies chloride (white AgCl precipitate), bromide (pale yellow AgBr), and iodide (yellow AgI) ions in solution. This test is one of the most commonly performed qualitative analyses in introductory chemistry courses. Silver nitrate is also used in electroplating, mirror manufacturing using Tollens' reagent for the silver mirror test, and water purification. For chemistry students, silver nitrate is a gateway to understanding solubility rules, precipitation reactions, and net ionic equations. The reaction AgNO3(aq) + NaCl(aq) -> AgCl(s) + NaNO3(aq) is a textbook example of a double displacement reaction. Silver nitrate also connects to photochemistry, oxidation-reduction reactions, and coordination chemistry. Its role in Tollens' test for aldehydes bridges inorganic and organic chemistry, making it one of the most versatile reagents in the teaching laboratory.

IUPAC Name

silver nitrate

CAS Number

7761-88-8

PubChem CID

24470

Molecular Formula

AgNO₃

Molar Mass

169.873 g/mol

State at STP

solid

Appearance

Colorless crystalline solid; stains skin black