Sodium nitrate is a chemical formula of white colour. It is an alkali metal nitrate as sodium belongs to the alkali Group I of the periodic table. A nitrate is any polyatomic ion made up of oxygen and nitrogen having a chemical formula NO[_{3}^{-}], which shows it as an anion. It is well known that sodium atoms donate one electron to form a cation, in order to achieve a stable electronic configuration. Hence, a cation of sodium and a polyatomic anion of nitrate combine with each other to form a neutral salt compound known as sodium nitrate and giving the sodium carbonate formula. Thus, the formula of sodium nitrate is given as NaNO[_{3}]. This is both the molecular formula of sodium nitrate and the chemical formula for sodium nitrate as is true for most other compounds.
General Physical Properties of Sodium Nitrate
The salt of sodium nitrate is also known as Chile saltpetre, whose largest deposits, historically, have been mined in Chile and Peru. The names of the mineral forms of sodium nitrate are nitratine, nitrate or soda niter. The salt of sodium nitrate has the physical form of a white powder or as colourless crystals.
The structural formula of sodium nitrate is given below showing the arrangement of the ions involved as in the answer to the question what is the chemical formula of sodium nitrate :
Some of the common physical properties of sodium nitrate are described below:
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The molecular weight of sodium nitrate as calculated from the sodium nitrate formula is 84.997 g/mol.
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It has a sweet odour.
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The density of sodium nitrate is 2.257 g/cm[^{3}].
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The melting point of sodium nitrate is 308 [^{0}]C and the boiling point is 380[^{0}]C.
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It is very much soluble in water, ammonia and hydrazine. It is slightly soluble in pyridine and insoluble in acetone since its an ionic compound as shown by the formula for sodium nitrate.
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The crystal structure of sodium nitrate is trigonal and rhombohedral.
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The salt of sodium nitrate has the capacity to hold and retain water.
Reactions and Uses
The industrial synthesis of sodium nitrate takes place by the neutralization of nitric acid with sodium carbonate or sodium bicarbonate. The reactions for this production methods are given below with the chemical formula of sodium nitrate and other compounds:
2HNO[_{3}] + Na[_{2}]CO[_{3}] → 2NaNO[_{3}] + H[_{2}]O + CO[_{2}]
HNO[_{3}] + NaHCO[_{3}] → NaNO[_{3}] H[_{2}]O + CO[_{2}]
Other methods also include the neutralization of nitric acid with sodium hydroxide or by the mixing of stoichiometric amounts of ammonium nitrate and sodium hydroxide, sodium bicarbonate or sodium carbonate.
One of the most common uses of sodium nitrate is the industrial production of fertilizers, pyrotechnics, and smoke bombs, glass and pottery enamels, food preservatives and solid rocket propellant. This is because it has a readily available nitrate anion, as is clear from the chemical formula of sodium nitrate which is a useful component in several reactions that are involved in these industrial processes.
Usually, refiners use sodium nitrate to make the hybrid aqua regia which is dissolved in gold and other different metals. It is also used for working with potassium nitrate and calcium nitrate for heat storage and for heat transfer in power plants that use solar energy for energy production. The wastewater treatment plants use sodium nitrate for the respiration of the facultative microorganisms. Nitrosomonas is a genus of specialized microorganisms, who consume nitrate preferentially over oxygen as it helps them to grow more rapidly in the treatment plants.
The use of sodium nitrate also includes its use as a food additive and as a food preservative and colour fixative in the cured meats and poultry.