Preparation, Properties, and Uses Of Nitrogen

Introduction

Nitrogen was discovered by Daniel Rutherford in 1772. The gas was named azote. Nitre is a widely known nitrogenous compound that helps in the derivation of nitrogen. Nitrogen is symbolized with N and its atomic number is 7. The element has an atomic mass of 14.0067.

What is Nitrogen?

Nitrogen is a non-metallic element. It is located in group 15 in the periodic table. It is found in gaseous form in ordinary temperatures; however, the gas can be transformed into a liquid or solid state by reducing its temperature.

The electronic configuration of nitrogen is $\mathrm{1s^{2}2s^{2}2p^{3}}$. The nitrogen molecule is symbolized as N2 known as Dinitrogen. The gas is tasteless, odourless, and colourless. It has an important role in the atmosphere as it occupies almost three-fourth part of the air. The gas shows inertness in the atmosphere and it does not burn. The gas occupies a four-fifth part by volume of air.

Figure 1 − Nitrogen’s “atomic structure”

Production of nitrogen

Nitrogen can be produced in various methods. It can be produced in laboratories. It can also be extracted from nitrogenous compounds and air.

Laboratory preparation on N2 − A solution of Sodium Nitrite $\mathrm{(NaNO_{2})}$ and Ammonium Chloride $\mathrm{(NH_{4}Cl)}$ in a saturated solution is heated to prepare Nitrogen.

$$\mathrm{NH_{4}l\:+\:NaNO_{2}\:\rightarrow\:NaCl\:+\:NH_{4}NO_{2}}$$

$$\mathrm{NH_{4}NO_{2}\:\rightarrow\:N_{2}\uparrow\:+\:2H_{2}O}$$

A round-bottomed flask is taken at first to contain the saturated solution. A delivery tube and a thistle funnel are fitted into the flask properly. The flask is gently heated and Nitrogen gas is produced by displacing water downward is collected.

Figure 2 − Laboratory preparation of Nitrogen

The collected nitrogen contains contaminated moisture. Anhydrous Calcium Chloride or Phosphorous Pentoxide is used to remove moisture from the collected nitrogen gas. Mercury is used for collecting nitrogen gas.

Other N2 obtaining methods − There are some other methods used for preparing nitrogen gas.

• Ammonium Dichromate can be thermally decomposed to prepare nitrogen gas. A violent reaction occurs while red crystals of Ammonium Dichromate are heated. In this reaction process, nitrogen is produced with the light flashing.

• Oxidation of Ammonia by Chlorine or red hot Copper Oxide can produce nitrogen gas. The equations are:

$$\mathrm{2NH_{3}\:+\:3CuO\:\rightarrow\:N_{2}\:+\:3H_{2}O\:+\:3Cu}$$

$$\mathrm{8NH_{3}\:+\:3Cl_{2}\:\rightarrow\:N_{2}\:+\:6NH_{4}Cl}$$

• Sodium Azide can also be thermally decomposed to produce nitrogen. Sodium or Barium Azide is heated to obtain nitrogen in pure form.

• Commercial production of $\mathrm{N_{2}}$ is done by the fractional distillation process of liquid air.

Physical and chemical properties of nitrogen

The physical and chemical characteristics of Dinitrogen or N2 are mentioned below −

Physical properties:

• Nitrogen is an odourless, tasteless, colourless gas.

• Nitrogen is soluble in water in very low amounts.

• The gas is not poisonous but the death of animals can occur under high concentrations of nitrogen due to less availability of oxygen in the air.

• Nitrogen melts at 63.2K and boils at 77.2K.

Chemical properties:

• Nitrogen usually does not participate in chemical reactions at normal temperatures. The gas neither burns nor supports combustion. The molecules are highly stable and it leads chemical inertness of nitrogen molecules at ordinary temperatures.

• Nitrides are covalent and ionic compounds of nitrogen. These are formed due to the reaction of nitrogen with some non-metals and metals at high temperatures.

• Ammonia is produced at 773 K by the reaction of nitrogen with hydrogen gas.

• In 2000 K, nitrogen molecules react with oxygen to form nitric oxide. The equation is −

$$\mathrm{N_{2}\:+\:O_{2}\:=\:2NO}$$

Applications of nitrogen

Nitrogen is one of the most used gases for producing chemical products. The different uses of nitrogen are as follows −

• N2 is mostly used for the preparation of Ammonia. Ammonia is used to make fertilizers, explosives, and other materials. Some important chemicals like Nitric acid and Calcium Cyanide are also produced from nitrogen.

• Some metallurgical operations require an inert atmosphere and it is accomplished under a nitrogen atmosphere.

• Cryosurgery requires the use of nitrogen. Preservation of biological material and freezing of food items require liquid nitrogen as a good refrigerant.

• Nitrogen is an inert diluent for most reactive chemicals.

• Perishable food items are packed by replacing oxygen with compressed nitrogen. This process helps to keep fresh food items for a long time.

• N2 inflation in car tires is far better than compressed air inflation. It helps the car to perform better. It also provides safety and economic benefit to vehicles.

• Nitrogen is used for Chemical Blanketing. Oxygen displacement is needed for highly explosive chemical plants and nitrogen is used for this process. It can prevent fire and explosion.

Conclusion

Nitrogen is a gaseous element found in-group 15 of the periodic table. It is tasteless, odourless, and colourless. The gas can be prepared in laboratories from a saturated solution of Ammonium Chloride and Sodium Nitrite. The gas is mainly used for the preparation of Ammonia in agricultural and industrial sectors. The gas is non-reactive at normal temperatures and it is used to create inert circumstances. Food storage units and freezers have the usage of liquid nitrogen. $\mathrm{N_{2}}$ is used for producing nitric acid.

FAQs

1. What are the conditions necessary for producing ammonia from $\mathrm{N_{2}}$?

The necessary conditions for preparing Ammonia from nitrogen are the presence of a catalyst, high pressure, and low temperature. Ammonia is produced in high amounts at low temperatures (720K-770K). It is an exothermic reaction. 200 atm is the ideal pressure to get a large amount of ammonia. A catalyst can increase the reaction rate. The catalyst is finely divided iron with molybdenum.

2. Why liquid nitrogen is used?

Liquid nitrogen is used for cooling computer components. It is used in medicines for unwanted skin, warts, and pre-cancerous cells. It is also used for preserving foods.

3. What is the molecular weight of nitrogen?

The nitrogen molecule is composed of two nitrogen atoms. The molecular weight of nitrogen is 14.0067 u.