Sodium Nitrate (NaNo3) - Structure, Preparation, Properties, Uses, FAQs

Sodium nitrate is an alkali metal nitrate salt and the chemical formula of sodium nitrate is NaNO₃. It is also known as Chile's saltpeter. Sodium nitrate is found exclusively in Chile and Peru. NO^-₃ The chemical name is nitrate. The compound consists of nitrate, NO^-₃ and the sodium cation that is Na⁺. Sodium nitrate is a white crystalline solid and has a high solubility in water. Sodium nitrate is also given the name white gold.

The mining of sodium nitrate from chile saltpeter was reduced now due to the introduction of Haber process that is ammonia is now produced in excess so it can be easily used for the production of sodium nitrate. Sodium nitrate is a very important compound since it contains nitrogen therefore it can be used as a fertilizer.

Sodium nitrate crystals

That was a strong oxidizing agent for flammable compounds and when heated to a temperature above 538 degrees Celsius it decomposes explosively. There are so many applications for this component and the main application for sodium nitrate in the field of agriculture is used as a fertilizer.

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Sodium nitrate structure

As the sodium nitrate, a compound contains one sodium-ion that is a Na⁺ and one nitrate ion that is NO^-₃, and the nitrate charge is -1. Where the nitrate ion has a trigonal planar geometry where the three oxygen atoms are bonded to the central atom nitrogen one doubly bonded and the two others are singly bonded to nitrogen. The overall formal charge on the nitrate and on is -1 and Na⁺ is coordinated to it as shown below. NaNO₃ The chemical name is sodium nitrate.

Structure of sodium nitrate

Preparation of sodium nitrate

Industrial sodium nitrate is prepared by a neutralization reaction between nitric acid and sodium carbonate. The following equation shows the preparation of sodium nitrate by these compounds.

NaHCO₃+HNO₃NaNO₃+H₂O+CO₂

Another method for the preparation of sodium nitrate is by the reaction of sodium bicarbonate with nitric acid. The following equation shows the preparation of sodium nitrate by this method.

Na₂CO₃+2HNO₃→2NaNO₃+CO₂+H₂O

By the reaction of nitric acid with sodium hydroxide sodium nitrate is obtained. The following equation shows the preparation of sodium nitrate by this method.

NaOH+HNO₃NaNO₃+H₂O

The reaction between sodium hydroxide and nitric acid is highly exothermic since sodium hydroxide is a strong base and also nitric acid is a strong acid. Show some other method is also adopted for the preparation of sodium nitrate that is by the reaction of sodium hydroxide with ammonium nitrate instead of the nitric acid. The following equation shows the preparation by this method.

NH₄NO₃+NaOH→NH₄OH+NaNO₃

Properties of sodium nitrate

From the sodium nitrate formula NaNO₃ we get that it is a compound formed by sodium and nitrate compounds. The preparation of sodium nitrate involves the use of strong acid and a strong base so the compound formed after the reaction will be a neutral salt. So sodium nitrate is a compound with a pH value of 7. Sodium nitrate is a white crystalline solid with a molecular mass of NaNO₃ is 84.9 g per Mol and has a density of 2.257 grams per cubic centimeter. The boiling point of sodium nitrate is 38 degrees Celsius and the melting point is 308 degrees Celsius.

As sodium nitrate is a crystalline structure and has two crystalline structures possible , rhombohedral and trigonal. Sodium nitrate has a sweet odor and is highly soluble in water at a temperature of 25 degrees Celsius. This compound also has a high solubility with ammonia. While dissolving sodium nitrate in water it dissociates into sodium ions and nitrate ions that are Na⁺ and NO^-₃. Sodium nitrate is a very strong oxidizing agent.

Effect of sodium nitrate on plant growth

Nitrogen is a very important mineral for the growth of plants. But as many of the soils do not contain nitrogen naturally so the application of nitrogen with any readily available nitrogenous fertilizers often makes the growth of plants effective. Sodium nitrate is the readily available nitrogen as fertilizer which increases crop growth and production.

The solubility of sodium nitrate in water is high so the application of sodium nitrate fertilizers over the soil should be well adapted. How many methods are there in order to reduce the wastage of sodium nitrate or the leaching of sodium nitrate with the water? Larger quantities are applied to place them in the sand just because of its solubility with the water. Several methods are adopted by the farmers to reduce the loss of sodium nitrate with water like applying grilling before plating and the second and the latter application as a side dressing for top dressing etc.

Also, students can refer,

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Sodium nitrate uses

• As it is a salt containing nitrate so the content of nitrogen is high it is used as fertilizer. Sodium nitrate fertilizer is now widely used in the agricultural field.
• A hybrid form of an Aqua regia is prepared with the help of sodium nitrate that has the ability to dissolve gold.
• Sodium nitrate is widely used as a preservative or as a food additive. It is also used to stabilize the meat color texture improvement and development of meat flavor, to reduce the microbial activities, etc. sodium nitrate is used.
• It is used as an oxidizer for several types of fireworks.
• This is one of the major components of instant cold packs.
• In some solar power plants, it is used for the storage and transfer of heat.
• Sodium nitrate is used for wastewater treatment by promoting the growth of Nitrosomonas bacteria.
• Sodium nitrate is used as a substitute for potassium nitrate that is used in gunpowder.

Decomposition of sodium nitrate

Most of the nitrates decompose upon heating and the thermal decomposition of sodium nitrate is taking place at a temperature above 800 degrees Celsius. The decomposition of sodium nitrate by the application of heat can be given by the following chemical equation.

2NaNO₃∆→ 2NaNO₂+O₂

From the NaNO3 decomposition oxygen is formed as a byproduct, as a colorless odorless gas after the reaction. And the reagent sodium nitrate is changed to sodium nitrite.

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NCERT Chemistry Notes:

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