Silver nitrate is a topical drug with antiseptic effects commonly used in wound management because it has a cautersized effect.
Chemical formula: AgNO3
Silver generally has an antimicrobial effect because it is able to cause precipitation in bacteria. Silver nitrate will bond with chloride ions and cause precipitation in the bacterial cellular components resulting in bacterial cell death. Silver nitrate is sometimes used for cauterization of wounds and tissues.
Silver Nitrate Making
Silver nitrate is prepared by attacking a piece of silver metal burned with nitric acid, either cold diluted, or concentrated heat:
3 Ag + 4 HNO3 (diluted) → 3 AgNO3 + 2 H2O + NO
Ag + 2 HNO3 (concentrate) → AgNO3 + H2O + NO2
Note the formation of NO and NO2 gases, which are toxic, and require that this reaction does not occur outside the hood’s range.
Physical and Chemical Properties of Silver Nitrate
- Physical appearance: Solid crystals are colorless, odorless, but with a very bitter taste.
- Molar period: 169,872 g/mole.
- Melting point: 209.7 ºC
- Boiling point: 440 ºC. However, at this temperature, it undergoes thermal decomposition, where silver metal is produced: 2 AgNO3(l) → 2 Ag(s) + O2 (g) + 2 NO2 (g)
- Therefore, there is no AgNO3 steam, at least not in terrestrial conditions.
- Solubility: AgNO3 is a highly water soluble salt, having a solubility of 256 g / 100 mL at 25 ºC. It is also soluble in other polar solvents such as ammonia, acetic acid, acetone, ether, and glycerol.
- Density: 4.35 g/cm3 at 24ºC (room temperature) 3.97 g/cm3 at 210ºC (only at melting point)
- Stability: AgNO3 is a stable substance as long as it is stored properly. It will not burn at any temperature, although it can decompose releasing toxic vapor from nitrogen oxides.
On the other hand, although silver nitrate is not flammable, it is a powerful oxidizing substance that, when in contact with organic matter and heat sources, it is able to trigger exothermic reactions and explosions.
In addition, this salt should also not be exposed to sunlight for too long, because the crystals become dark due to the formation of silver oxide.
Silver Nitrate Uses
There are dozens of uses of silver nitrate, including the simplest for the treatment of warts. Silver nitrate is made from a silver metal dissolving reaction using nitric acid.
Some of the main uses of silver nitrate are as follows:
- As a precursor for the making of various silver compounds, both inorganic silver, and organic silver compounds.
- As an antiseptic and external medicine, especially for the treatment of warts and wound
- As a reagent against adequacy in chemical reactions.
- Used for the manufacture of silver acetate compounds, through a reaction between silver nitrate and sodium acetate.
- Used as raw material for the manufacture of disianoargentat.
Dangers of silver nitrate solution
AgNO3 or also called silver nitrate is one of the chemicals that has a corrosive effect, namely damaging the area that comes into contact with it. In medicine, this solution is often used, for example to help stop bleeding by closing open blood vessels, as one of the preferred drugs for removing skin warts, etc.
When exposed to the skin, silver nitrate will cause purple, brown, or blackish stains, which can generally disappear on their own within a certain time (depending on the concentration of silver nitrate on the skin).
But in the long run or in high concentrations of exposure, silver nitrate can result in burns to the skin. So it is important to use gloves to avoid exposure to the skin. When using silver nitrate, it is also recommended to use a mask because silver nitrate inhaled can cause irritation of the mucous membranes and upper airways.
In addition, when ingested silver nitrate can result in burns to the digestive organs that it passes through. When the splash hits the eye, it can also cause damage to the eyes, so it is also important to use eye protection glasses when using this compound.
When exposed to silver nitrate on the skin, the first aid that can be done is to keep the silver nitrate away from the body, and wash the silver nitrate with running water. And be sure at a later date if you are going to use silver nitrate, don’t forget to use personal protective equipment (PPE) as mentioned above, namely masks, gloves, and protective goggles.
If your black spots are widening, or in the contact area with pain, redness, or blisters, please check with your GP at the nearest emergency room for help.