Nitric acid belongs to the group of inorganic acids. It is also known as aqua fortis meaning strong water, aqua Valens meaning powerful water and spirit of nitre. It is an acid that is both extremely corrosive and toxic and therefore direct contact with it can result in sever burns. It is colourless when pure but has a yellowish appearance when it is old due to the collection of nitrogen oxides. Upon distillation, nitric acid in its pure form begins to boil at 78.2 degrees Celsius and becomes solid when it is well cooled.
Nitric acid is also a strong and powerful oxidizing agent which nitrates many organic compounds. It reacts with alkalis, basic oxides, and carbonates to form salts. Nitric is made by combining nitrogen dioxide and water in the presence of air. During this process, the air oxidizes nitrous acid which is also produced in the process. The salts produced by nitric acid are known as nitrates and they are water soluble and crystallize well. These salts decompose when heated at high temperatures. Nitric acid is very important in industries and is a common reagent used in laboratories.
The following are the main uses of nitric acid:
- It is used in the production of ammonium nitrate for fertilizers.
- It is used for making plastics
- It is used in the manufacture of dyes
- It is used for making explosives such as nitroglycerine
- When it is combined with hydrochloric acid it forms an element called aqua regia which is a reagent that is capable of dissolving gold and platinum.
- It is used in a colorimetric test to distinguish heroin and morphine.
- Nitric acid is commonly used in science laboratories at schools for experimenting when specifically testing for chloride. This is done by adding a sample with silver nitrate solution and nitric acid to test if a white precipitate, silver chloride is present.
- Nitric acid is used in the field of medicine in its pure state as a caustic to get rid of chancres and warts. Diluted solutions are used in the treatment of dyspepsia.
This acid is dangerous because it is highly corrosive and has oxidizing properties and as such it must be handled with great care. When handling nitric acid, one must wear protective gears especially to protect the eyes. The skin must also be protected because when nitric acid comes in contact with the skin, it results in a yellow discolouration. To counteract this, use mild alkalis along with opium to relieve pain. If a large amount gets in contact with the skin, it can cause fatal burns. When mixed with metals or organic compounds, nitric acid produces fumes. Do not inhale these fumes as the result may be fatality. Nitric acid does not burn directly but when it oxidizes organic matter it makes them highly flammable. Poisoning caused by strong, undiluted nitric acid leads to gastroenteritis, bloody diarrhea and burning pain in the abdomen and oesophagus. Blood in the urine is also possible.