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.
Nitrate vs Nitrite
Nitrate vs Nitrite

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)

Characteristics Nitrate Nitrite
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. 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.
Oxidation State The oxidation state of nitrogen in nitrates is +5. The oxidation state of nitrogen in nitrite is +3.
Structure Nitrates have a trigonal planar structure. Nitrites have a bent molecular structure.
Molecular Formula The molecular formula of nitrate is NO3. The molecular formula of nitrite is NO2.
Molar Mass The molar mass of nitrate is 62 g/mol. The molar mass of nitrite is 46.01 g/mol.
Oxidizing Nature Nitrates act as oxidizing agents. Nitrites can act as both oxidizing and reducing agents.
Atoms Nitrates consist of a nitrogen atom and three oxygen atoms. Nitrites consist of a nitrogen atom and two oxygen atoms.
Conjugate Acid The conjugate acid of nitrates is nitric acid. The conjugate acid of nitrite is nitrous acid.
Chemical Process Nitrates are reduced to form nitrites. Nitrites are oxidized to form nitrates.
Stability Nitrates are comparatively more stable. Nitrites are comparatively less stable than nitrates.
Hazardous Concentrations The lethal dose of nitrates is usually high as these are less hazardous. The lethal dose of nitrite is usually high as it is more hazardous.
Uses Nitrates salts are used in fertilizers and explosives. Inorganic nitrites are used as food preservatives.
Examples Some examples of nitrates include sodium nitrate, aluminium nitrate, magnesium nitrate, etc. Some examples of nitrites include sodium nitrite, potassium nitrite, calcium nitrite, etc.

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/

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