Chemical formula: HNO3 Molar mass: 63.012 g·mol−1 Melting point: −42 °C Boiling point: 83 °C
WHAT IS NITRIC ACID?
Nitric acid is a highly corrosive mineral acid. It is also referred to as the spirit of nitre and aqua fortis. It is colorless. However old samples of nitric oxides may turn yellow due to the decomposition into oxides of nitrogen and water.
Fuming nitric acid is a solution containing more than 86% of nitric acid in water. The fuming nitric acid can be further divided into red fuming nitric acid (when the concentration is above 86%) and white fuming nitric acid ( when the concentration is more than 95%).
STRUCTURE OF NITRIC ACID
Nitric acid has a planar structure. Nitrogen is attached to three atoms of oxygen. Two of the nitrogen-oxygen bonds are equivalent and show resonance with double bond character.
This is the structure of nitric acid with its resonance forms.
USES OF NITRIC ACID
1. NITRIC ACID IN FERTILIZERS
Nitric acid is an essential component of fertilizers.It is used to most in the production of fertilizers.It is neutralized with ammonia to give ammonia nitrate.
2. PRECURSOR TO ORGANIC NITROGEN COMPOUNDS
Nitration is carried out with the help of nitric acid for the addition of the nitro group. Most of the derivatives of aniline are prepared by the nitration of aromatic compounds which is then followed by reduction. Nitration includes combining nitric and sulphuric acid in order to form nitronium ion that reacts electrophilically with aromatic compounds like benzene.
3. NITRIC ACID AS AN OXIDANT
Cyclohexanone undergoes oxidation with nitric acid which is a precursor form adipic acid.
4. ROCKET PROPELLANT
NItric acid has been used in various forms as an oxidizer in liquid-fueled rockets. These forms include red fuming nitric acid, white fuming nitric acid as well as mixtures of sulphuric acid along with HF inhibitor.
5. ANALYTICAL REAGENT
Dilute nitric acid is used to determine metal traces in solutions. For such determinations, ultrapure trace metal grade acid is required because a small number of metal ions could affect the result of the analysis. In electrochemistry, nitric acid is used in the purification processes of raw carbon nanotubes as well as a chemical doping agent for organic semiconductors.
Low concentrations of nitric acid(approximately 10%) are used to artificially age pine and maple to produce a grey-gold color which gives an old wax more oil finished wood look.
5–30% nitric acid and 15–40% phosphoric acid is commonly used for cleaning and dairy equipment to remove primarily calcium and magnesium compounds which are produced from the use of hard water during production or purification, or it could be deposited from the process stream.
The corrosive effects of nitric acid are used in pickling stainless steel as well as for cleaning silicon wafers in electronics. Nitric acid is used with hydrochloric acid or alone to clean glass coverslips and glass slides for high-end microscopy applications. It is also used to clean glass before silvering while producing silver mirrors.
8. IN DAILY LIFE
One of the most common uses of nitric acid is that it is found as a reagent in the school labs. It is also used for spot tests of alkaloids such as LSD. It is also used to perform the colorimetric analysis, in which using nitric acid one can differentiate between heroin and morphine.
Safety issues Nitric acid is one among the most corrosive acids and is also a strong oxidizing agent. One of the significant hazard posed by it is skin burns. The chemical burns are fast and painful as it carries our acid hydrolysis faster with fats (ester) and proteins (amide). It leaves a yellow stain as it reacts with keratin. The yellow stains turn orange when neutralized. Washing it with water for 10-15 minutes can provide relief in case of burns.