Nitrate vs Nitrite- Definition, 13 Major Differences, Examples

Nitrate Definition

Nitrate is a nitrogen oxoanion formed by the loss of hydrogen from nitric acid with a charge of -1, one nitrogen atom, and three oxygen atoms.

• It is a polyatomic ion with the molecular formula NO₃^– that is commonly used in the form of salts in fertilizers and explosives.
• Nitrate is a monovalent inorganic anion and a conjugate base of nitric acid. It can form salts with various metals.
• Nitrate ion has a trigonal planar structure with a central nitrogen atom that is surrounded by three identically bonded oxygen atoms.
• The overall charge of the ion is -1, where each oxygen atom carries a -2/3 charge while nitrogen carries a charge of +1.
• Nitrates can acts as oxidizing agents as the nitrogen atom in the molecule has an oxidation state of +5.
• Nitrates are also essential in the diet of living beings which is consumed in the form of inorganic nitrates present in leafy vegetables. Drinking water is also a dietary source of nitrates.
• Nitrate salts occur on earth in the form of deposits and rocks. These are produced from nitrogen compounds by nitrifying bacteria.
• The most important use of nitrate is as fertilizers in agriculture as a result of their high solubility and biodegradability.
•  In industries, nitrates are used as oxidizing agents during the production of metal products.
• Some examples of nitrates include sodium nitrate, aluminium nitrate, magnesium nitrate, etc.

Nitrite Definition

Nitrite is a polyatomic anion of nitrogen formed by the loss of hydrogen atoms from nitrous acid with the charge of -1, one nitrogen atom, and two oxygen atoms.

• Nitrites are primarily produced as intermediate products during the oxidation of ammonia to nitrate.
• The molecular formula of nitrite is NO₂^– and it is the conjugate acid of nitrous acids, HNO₂.
• However, the term nitrite might also be used to refer to organic compounds with the –ONO group that are esters of nitrous acid.
• Nitrites can act both as oxidizing and reducing agents as the nitrogen atom in the molecule has the oxidation state of +3.
• The structure of the nitrite ion has a bent geometry with the O-N-O bond angle around 120°C.
• The ion has a symmetrical structure where both of the N-O bonds have equal lengths and bond angles. The ion exists in two distinct forms that are mirror images of each other, and thus, it has a resonance hybrid.
• Nitrite is an essential intermediate in the nitrogen cycle as it is reduced to nitric oxide or ammonia in the presence of nitrifying bacteria.
• It is also used in azo dyes and other colorants via diazotization. Some nitrites like sodium nitrite are also used in food preservation.
• The presence of nitrite above the desired levels in food and water samples can result in various diseases in humans. Nitrites in diet form N-nitrosamines which are likely to cause stomach cancer.

13 Key Differences (Nitrate vs Nitrite)

Examples of Nitrate

Magnesium Nitrate

• Magnesium nitrate is an inorganic nitrate salt of magnesium with the molecular formula- Mg(NO₃)₂.
• Magnesium nitrate is a hygroscopic substance that quickly forms hexahydrate if left in the air. The hygroscopic form of the compound is Mg(NO₃)₂.6H₂O.
• It exists in the form of a white crystalline solid and produces toxic oxides of nitrogen when heated.
• It can be naturally extracted from mines and caverns, but the commercial production of magnesium nitrate is by the reaction of nitric acid and magnesium salts.
• Magnesium nitrate readily reacts with alkali metal hydroxides to form alkali nitrates.
• As it is hygroscopic and has a high affinity for water, combustion of magnesium nitrate results in the decomposition into magnesium oxide, oxygen, and other oxides.

Examples of Nitrite

Sodium Nitrite

• Sodium nitrite is an inorganic sodium salt with the molecular formula NaNO₂.
• It exists in the form of a yellowish-white crystalline solid that is commonly used as a food preservative.
• It is non-combustible by itself but might accelerate the combustion of other materials. In large quantities, however, it might result in fire and explosions.
• Sodium nitrite has multiple industrial applications and is often considered the most important nitrite salt.
• It is used as a precursor in various products like medicines, dyes, and fertilizers, but its most common use is as a food additive.
• Despite its applications in industries, it can be lethal to humans if consumed at a dose of more than 71 mg/kg.
• Even though it doesn’t occur naturally in vegetables, high levels of sodium nitrite have been observed in such products due to its overuse as fertilizers.

References

1. Gautum SD, Pant M and Adhikari NR (2016). Comprehensive Chemistry, Part 2. Sixth Edition. Heritage Publishers and Distributors Pvt. Ltd
2. National Center for Biotechnology Information. PubChem Compound Summary for CID 943, Nitrate. https://pubchem.ncbi.nlm.nih.gov/compound/Nitrate. Accessed Mar. 26, 2021.
3. National Center for Biotechnology Information. PubChem Compound Summary for CID 25212, Magnesium nitrate. https://pubchem.ncbi.nlm.nih.gov/compound/Magnesium-nitrate. Accessed Mar. 26, 2021.
4. National Center for Biotechnology Information. PubChem Compound Summary for CID 23668193, Sodium nitrite. https://pubchem.ncbi.nlm.nih.gov/compound/Sodium-nitrite. Accessed Mar. 26, 2021.
5. https://pediaa.com/difference-between-nitrate-and-nitrite/ 
6. https://www.differencebetween.com/difference-between-nitrate-and-vs-nitrite/