Ammonia - Structure, Preparation, Uses, FAQs

Ammonia - Structure, Preparation, Uses, FAQs

Edited By Team Careers360 | Updated on Jul 02, 2025 04:43 PM IST

Ammonia is a colorless gas with a pungent odour, having chemical formula NH3 is commonly used as a fertilizer and in various industrial applications. Hydrogen and nitrogen are its components. It is also known as ammonium hydroxide in its aqueous form. It can be dangerous in concentrated form. An ammonia cylinder has a density of 0.769 kg/m3 at STP, making it lighter than air. TNT and nitrocellulose are also created from Ammonia. In addition, soda ash is produced with it, as well as nitric acid using the Ostwald process.

This Story also Contains
  1. Characteristics of Ammonia Gas - NH
  2. Ammonia - NH3 preparation of ammonia
  3. Uses of Ammonia (NH3)
Ammonia - Structure, Preparation, Uses, FAQs
Ammonia - Structure, Preparation, Uses, FAQs

Characteristics of Ammonia Gas - NH

NH3

Ammonia

Molecular Weight/ Molar Mass

17.031 g/mol

Density

0.73 kg/m³

Ammonia boiling point

-33.34 °C

Melting Point

−77.73 °C

The compound ammonia gas is known as a weak base since it forms ammonia salts when combined with a variety of acids. The result of the reaction between ammonia gas and hydrochloric acid is ammonium chloride. The ammonium cation NH4+ is found in all ammonia salts produced through such acid-base reactions. Liquid ammonia has also been found to possess weak acidic properties and, therefore, can be considered an amphoteric compound. With some alkali metals and alkaline earth metals, ammonia forms amides due to its acidic qualities. The NH3 molecule is also known to undergo self-dissociation once it is dissolved in water. Ammonia molecules undergo molecular autoionization, which forms their conjugate bases (NH2–) and acids (NH4+). Below is an illustration of the structure of the ammonium cation.

Ammonia Structure or NH3 structure:

Ammonia Structure

As an example of an equilibrium reaction for this autoionization process, we have:

2NH3 ⇌ NH2– + NH4+

The weak base nature of ammonia makes it a useful buffer (for maintaining a constant pH).

Ammonia - NH3 preparation of ammonia

Sodium hydroxide or calcium hydroxide are powerful alkalis which are used to prepare ammonia in the laboratory.

2NH4Cl + Ca (OH)2 → CaCl2 + 2H2O + 2NH3(g)

Alternatively, the gas can be made by heating concentrated ammonium hydroxide.

Under high pressure and presence of a catalyst, nitrogen and hydrogen are directly combined to produce ammonia in the Haber Process.

Uses of Ammonia (NH3)

  • Fertilizing crops with it produces higher yields

  • As a cleaner, stainless steel and glass can be cleaned with NH3 inside a home

  • Food products containing it provide antimicrobial properties

  • There are many industries that use it for fermentation

  • The refrigerant used in refrigeration is this

  • The pH of fermentation processes must be adjusted

  • Hence, it neutralizes emissions of diesel engine pollutants such as nitrogen oxides

  • For rocket engines, it is used as a fuel

  • In textile industries, it is used

  • for manufacturing synthetic fibres like rayon and nylon

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Frequently Asked Questions (FAQs)

1. Is ammonia NH₃ or NH₄⁺?

Ammonia formula is NH₃. The ion NH₄⁺ is called the ammonium ion. 

2. Is NH₃ a gas?

Yes, NH₃ (ammonia) is a colorless gas with a distinct, pungent odor at room temperature. It is commonly used in fertilizers and as a cleaning agent.

3. What is the structure of NH₃?

The structure of NH₃ (ammonia) is trigonal pyramidal, with the nitrogen atom at the top and three hydrogen atoms at the base. The nitrogen atom has a lone pair of electrons, which contributes to the molecule's shape and polarity. The bond angle between hydrogen, nitrogen, and hydrogen atoms (H-N-H) is 107°.

4. Is NH3 base or acid?

NH₃ (ammonia) is considered a weak base because it can accept protons (H⁺) from acids in aqueous solutions, forming ammonium ions (NH₄⁺).

 

5. What is the Haber process, and why is it important?
The Haber process is an industrial method for synthesizing ammonia from nitrogen and hydrogen gases under high pressure and temperature, using an iron catalyst. It's important because it revolutionized fertilizer production, significantly impacting agriculture and global food supply.
6. How does temperature affect the yield of ammonia in the Haber process?
In the Haber process, lower temperatures favor higher ammonia yields because the reaction is exothermic. However, the reaction rate decreases at lower temperatures, so an optimal temperature (around 450°C) is used to balance yield and reaction rate.
7. Why is high pressure used in the Haber process?
High pressure is used in the Haber process because it shifts the equilibrium towards the product side according to Le Chatelier's principle. The reaction produces fewer gas molecules than it consumes, so increased pressure favors the forward reaction, increasing ammonia yield.
8. What role does the iron catalyst play in the Haber process?
The iron catalyst in the Haber process lowers the activation energy of the reaction, increasing the rate at which equilibrium is reached. It does not affect the equilibrium position or the final yield of ammonia but allows the reaction to proceed at a practical rate.
9. How does ammonia behave as a Brønsted-Lowry base?
Ammonia acts as a Brønsted-Lowry base by accepting a proton (H+) from acids. It forms the ammonium ion (NH4+) when it gains a proton, making it a weak base in aqueous solutions.
10. What is the molecular structure of ammonia?
Ammonia (NH3) has a trigonal pyramidal structure with the nitrogen atom at the apex and three hydrogen atoms forming the base. The bond angle between N-H bonds is approximately 107.3°, slightly smaller than the tetrahedral angle of 109.5° due to the lone pair of electrons on the nitrogen atom.
11. Why is ammonia considered a polar molecule?
Ammonia is polar because of its asymmetric structure and the difference in electronegativity between nitrogen and hydrogen. The nitrogen atom has a partial negative charge, while the hydrogen atoms have partial positive charges, creating a net dipole moment.
12. How does the lone pair of electrons on nitrogen affect ammonia's properties?
The lone pair of electrons on nitrogen gives ammonia its basic properties, allows it to form hydrogen bonds, and contributes to its high solubility in water. It also affects the molecule's shape and reactivity, making ammonia a good electron donor in chemical reactions.
13. What is the hybridization of the nitrogen atom in ammonia?
The nitrogen atom in ammonia is sp³ hybridized. This hybridization allows for the formation of three sigma bonds with hydrogen atoms and accommodates the lone pair of electrons, resulting in the trigonal pyramidal structure.
14. How does ammonia form hydrogen bonds?
Ammonia forms hydrogen bonds through its lone pair of electrons on nitrogen, which can interact with hydrogen atoms from other ammonia molecules or water molecules. The N-H···N hydrogen bond in ammonia is weaker than the O-H···O hydrogen bond in water.
15. Why is liquid ammonia used as a solvent in some chemical reactions?
Liquid ammonia is used as a solvent because it can dissolve many organic and inorganic compounds. Its high polarity, ability to form hydrogen bonds, and low boiling point make it useful for reactions that require anhydrous conditions or low temperatures.
16. How is the strength of aqueous ammonia solutions typically expressed?
The strength of aqueous ammonia solutions is typically expressed as a percentage by weight of NH3 in water. Common concentrations include 28-30% for household ammonia and up to 35% for industrial use.
17. What safety precautions should be taken when handling ammonia?
Safety precautions for handling ammonia include using proper ventilation, wearing protective equipment (gloves, goggles, and respiratory protection), avoiding skin or eye contact, and having emergency shower and eyewash stations nearby. Anhydrous ammonia requires special handling due to its corrosive and toxic nature.
18. How does ammonia contribute to the nitrogen cycle?
Ammonia plays a crucial role in the nitrogen cycle as an intermediate compound. It's produced by nitrogen-fixing bacteria, decomposition of organic matter, and industrial processes. Plants can absorb ammonia directly or after it's converted to nitrates by nitrifying bacteria.
19. What are the environmental concerns associated with ammonia?
Environmental concerns with ammonia include its contribution to air pollution, water eutrophication, and soil acidification. Excess ammonia in ecosystems can disrupt natural nutrient balances and harm aquatic life. Industrial ammonia production also contributes to greenhouse gas emissions.
20. What is the conjugate acid of ammonia?
The conjugate acid of ammonia is the ammonium ion (NH4+). When ammonia accepts a proton in an acid-base reaction, it forms this positively charged ion.
21. How does ammonia's basicity compare to other nitrogen-containing compounds?
Ammonia is more basic than most primary amines due to the absence of electron-withdrawing alkyl groups. However, it is less basic than many secondary and tertiary amines because the alkyl groups in these amines increase electron density on the nitrogen atom.
22. How does ammonia react with water?
When ammonia dissolves in water, it undergoes a reversible reaction:
23. What is the difference between anhydrous ammonia and aqueous ammonia?
Anhydrous ammonia is pure NH3 in gaseous or liquid form, while aqueous ammonia (also called ammonia water or ammonium hydroxide) is a solution of ammonia dissolved in water. Anhydrous ammonia is more concentrated and reactive than aqueous ammonia.
24. How does ammonia's boiling point compare to other similar molecules?
Ammonia has a relatively low boiling point (-33.34°C) compared to water (100°C), despite both forming hydrogen bonds. This is because ammonia forms weaker hydrogen bonds than water due to nitrogen's lower electronegativity compared to oxygen.
25. What is the role of ammonia in the production of fertilizers?
Ammonia is a key component in fertilizer production. It's directly used as anhydrous ammonia fertilizer or converted into other nitrogen-containing fertilizers like urea, ammonium nitrate, and ammonium phosphates. These fertilizers provide essential nitrogen for plant growth.
26. How does ammonia contribute to the formation of smog?
Ammonia contributes to smog formation by reacting with nitrogen oxides and sulfur dioxide in the atmosphere to form fine particulate matter (PM2.5). These particles can remain suspended in the air, reducing visibility and causing respiratory issues.
27. What is the significance of ammonia's dipole moment?
Ammonia's dipole moment (1.47 D) is significant because it influences the molecule's polarity, solubility, and ability to form hydrogen bonds. This dipole moment contributes to ammonia's unique properties, such as its high solubility in water and its ability to act as a polar solvent.
28. How does the concept of VSEPR theory explain ammonia's structure?
VSEPR (Valence Shell Electron Pair Repulsion) theory explains ammonia's structure by considering the repulsion between electron pairs around the central nitrogen atom. The three bonding pairs and one lone pair arrange themselves to minimize repulsion, resulting in the trigonal pyramidal shape with bond angles slightly less than tetrahedral.
29. What is ammonia's role in biological systems?
In biological systems, ammonia is a crucial component of amino acid and nucleic acid synthesis. It's also a waste product of protein metabolism in animals, which is converted to urea or uric acid for excretion. In plants, ammonia is an important source of nitrogen for growth.
30. How does ammonia behave as a ligand in coordination compounds?
Ammonia acts as a monodentate ligand in coordination compounds, donating its lone pair of electrons to form a coordinate covalent bond with metal ions. This ability makes ammonia important in forming many transition metal complexes, such as [Cu(NH3)4]2+.
31. What is the relationship between ammonia and amines?
Ammonia is the simplest amine, with the formula NH3. Other amines can be considered derivatives of ammonia where one or more hydrogen atoms are replaced by alkyl or aryl groups. The chemical properties of ammonia and amines are similar due to the presence of the lone pair on nitrogen.
32. How does ammonia's molecular mass affect its rate of diffusion?
Ammonia's relatively low molecular mass (17 g/mol) allows it to diffuse quickly in air compared to heavier gases. According to Graham's law of diffusion, the rate of diffusion is inversely proportional to the square root of the molecular mass, so ammonia diffuses faster than most common gases.
33. What is the significance of ammonia's critical temperature and pressure?
Ammonia's critical temperature (132.4°C) and pressure (113.3 atm) are important in industrial applications, particularly refrigeration. Above the critical point, ammonia cannot be liquefied by pressure alone, which is crucial for designing ammonia-based refrigeration systems and determining storage conditions.
34. How does ammonia participate in acid-catalyzed reactions?
In acid-catalyzed reactions, ammonia can act as a nucleophile due to its lone pair of electrons. It can attack electrophilic centers, such as carbonyl groups, leading to the formation of various nitrogen-containing compounds. This reactivity is important in organic synthesis and biochemical processes.
35. What is the relationship between ammonia and the ammonium ion in aqueous solution?
In aqueous solution, ammonia exists in equilibrium with the ammonium ion:
36. How does ammonia's polarity affect its solubility in different solvents?
Ammonia's polarity makes it highly soluble in polar solvents like water due to the formation of hydrogen bonds. It is less soluble in non-polar solvents. This polarity-based solubility follows the "like dissolves like" principle in chemistry.
37. What is the significance of ammonia's ionization energy?
The ionization energy of ammonia (1521 kJ/mol) is relatively high due to the strong attraction between the nitrogen nucleus and its electrons. This high ionization energy contributes to ammonia's stability and influences its reactivity in chemical processes.
38. How does ammonia behave in redox reactions?
In redox reactions, ammonia typically acts as a reducing agent due to the presence of hydrogen atoms. It can be oxidized to nitrogen gas, nitric oxide, or nitrogen dioxide depending on the oxidizing agent and conditions. For example, ammonia can reduce copper(II) ions to copper metal in aqueous solution.
39. What is the importance of ammonia in the production of plastics and fibers?
Ammonia is a key starting material for producing many plastics and synthetic fibers. It's used to make nylon, acrylics, and other nitrogen-containing polymers. Ammonia derivatives like urea are also used in the production of resins and adhesives.
40. How does ammonia's structure contribute to its ability to form complexes with transition metals?
Ammonia's lone pair of electrons on the nitrogen atom allows it to act as a Lewis base, donating electrons to form coordinate covalent bonds with transition metal ions. This electron-donating ability, combined with its small size, makes ammonia an excellent ligand for forming stable metal complexes.
41. What is the role of ammonia in the Ostwald process?
In the Ostwald process, ammonia is the starting material for the industrial production of nitric acid. Ammonia is first oxidized to nitric oxide (NO) over a platinum-rhodium catalyst, then further oxidized to nitrogen dioxide (NO2), which is absorbed in water to form nitric acid (HNO3).
42. How does the presence of ammonia affect the pH of soil?
Ammonia can increase soil pH (make it more alkaline) when applied as a fertilizer. This is because ammonia reacts with water in the soil to form ammonium ions and hydroxide ions. Over time, nitrification of ammonium can lead to soil acidification, so the long-term effect on soil pH can be complex.
43. What is the significance of ammonia's heat of vaporization?
Ammonia's high heat of vaporization (23.35 kJ/mol) makes it useful as a refrigerant. When ammonia evaporates, it absorbs a large amount of heat from its surroundings, providing an efficient cooling effect. This property is utilized in industrial refrigeration systems and some air conditioning units.
44. How does ammonia contribute to the formation of atmospheric aerosols?
Ammonia plays a crucial role in atmospheric aerosol formation by reacting with acidic species like sulfuric acid and nitric acid to form ammonium salts. These salts can nucleate to form new particles or condense onto existing particles, contributing to the formation of secondary inorganic aerosols in the atmosphere.
45. What is the relationship between ammonia and amino acids?
Ammonia is a key component in the biosynthesis of amino acids. In plants and microorganisms, ammonia is incorporated into organic compounds through the glutamate synthase cycle to form glutamate, which serves as a precursor for other amino acids. In the laboratory, ammonia is also used in the synthesis of amino acids.
46. How does ammonia's structure affect its infrared spectrum?
Ammonia's trigonal pyramidal structure and the presence of N-H bonds give rise to characteristic absorption bands in its infrared spectrum. The N-H stretching vibrations appear around 3300-3500 cm⁻¹, while bending vibrations are observed around 1600 cm⁻¹. The spectrum also shows inversion doubling due to the molecule's ability to invert through a planar transition state.
47. What is the significance of ammonia's autoionization in liquid ammonia?
In liquid ammonia, a small fraction of molecules undergo autoionization:
48. How does ammonia participate in the Kjeldahl method?
In the Kjeldahl method, a technique for determining the nitrogen content in organic samples, ammonia plays a crucial role. The organic nitrogen in the sample is converted to ammonium sulfate through digestion with sulfuric acid. The solution is then made alkaline, converting ammonium to ammonia, which is distilled and quantitatively analyzed to determine the original nitrogen content.
49. What is the importance of ammonia in the production of explosives?
Ammonia is a key raw material in the production of many explosives. It's used to manufacture ammonium nitrate, a common component in industrial explosives and fertilizers. Ammonia is also used in the production of nitric acid, which is essential for making other explosive compounds like TNT and nitroglycerin.
50. How does ammonia's Lewis structure relate to its molecular geometry?
Ammonia's Lewis structure shows a central nitrogen atom with three single bonds to hydrogen atoms and one lone pair of electrons. This electron arrangement leads to its trigonal pyramidal geometry, as predicted by VSEPR theory. The lone pair occupies one of the four tetrahedral positions around the nitrogen, pushing the three N-H bonds slightly closer together than in a perfect tetrahedron.
51. What is the role of ammonia in the DeNOx process?
In the DeNOx process, also known as selective catalytic reduction (SCR), ammonia is used to reduce nitrogen oxides (NOx) in exhaust gases from power plants and vehicles. Ammonia reacts with NOx in the presence of a catalyst, converting them to harmless nitrogen gas and water vapor, thus reducing air pollution.
52. How does ammonia's behavior as a base differ in water compared to in liquid ammonia?
In water, ammonia acts as a weak base, partially accepting protons to form ammonium ions. In liquid ammonia, however, it acts as a much stronger base due to the autoionization of ammonia (2NH3 ⇌ NH4+ + NH2-). In this environment, ammonia can deprotonate even weak acids, making it a more potent

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Questions related to

Have a question related to ?

Correct Answer: clues


Solution : The most appropriate option is the third option.

Explanation:
Clues refer to hints, evidence, or information that helps in understanding or solving something. In the context of the passage, moons, asteroids, and comets provide crucial information or hints about the formation and evolution of the solar system. They offer valuable insights that aid in understanding how the solar system came into existence and how it has changed over time.

The meanings of the other options are as follows:

  • Sets refer to a group of related objects or things.
  • Derivations refer to the process of obtaining something from a source or origin.
  • Biases refer to prejudices or inclinations that affect judgement or decision-making based on partiality or preference.

Question : Comprehension:
In the following passage, some words have been deleted. Read the passage carefully and select the most appropriate option to fill in each blank.
The solar system is made up of the sun, planets, moons, asteroids, and comets that 1.______ around it. Its mysteries and wonders have captured the imagination of people from all walks of life, and it continues to be an area of active research and exploration. The sun is at the centre of the solar system and is the largest object in it. The eight planets in the solar system, 2._________ Earth, orbit around the sun in nearly circular paths. While the sun is at the centre of the solar system and dominates its gravitational pull, each planet has its own unique set of characteristics that makes it a fascinating object to study. Each planet in the solar system has unique characteristics and features. 3._________ planets, such as Mercury and Venus, are small and rocky, while others, like Jupiter and Saturn, are much larger and made up mostly of gas. The outer planets, Uranus and Neptune, are 4._______ as 'ice giants' because they contain more water, ammonia, and methane than the gas giants. In addition to the planets, the solar system also has numerous moons, asteroids, and comets. These objects provide important 5.______ about the formation and evolution of the solar system.
Question:
Select the most appropriate option to fill in the blank 2.

Option 1: excluding

Option 2: diluting

Option 3: dissolving

Option 4: including

Correct Answer: including


Solution : The most appropriate option is the fourth option.

Explanation: Including means to contain as part of a whole. In this context, it implies that among the eight planets in the solar system, Earth is one of them. "The eight planets in the solar system, including Earth, orbit around the sun in nearly circular paths."

The meanings of the other options are as follows:

  • Excluding means not taking into account or not including.
  • Diluting means to make something weaker or less concentrated.
  • Dissolving means becoming incorporated into a liquid and forming a solution.

 

Correct Answer: 14:3


Solution : The correct answer is 14:3.

The mass ratio of nitrogen to hydrogen is 14:3. As a result, three hydrogen atoms and one nitrogen atom combine to form a molecule with a molecular weight of 17. Ammonia, or NH₃, is the formula of the compound created in the specified ratio and calculated molecular weight.

Correct Answer: orbit


Solution : The most appropriate option is the second option.

Explanation:
Orbit is the correct word to use in this context, as it refers to the motion of celestial objects around a central body due to gravitational pull. In the context of the solar system, planets, moons, asteroids, and comets orbit (move in a curved path) around the sun.

The meanings of the other options are as follows:

  • Form: It refers to the process of something coming into existence or taking shape.
  • Stick: Implies adherence or attachment, which doesn't relate to the movement of celestial bodies in space.
  • Fly: It suggests movement through the air rather than the specific motion of objects in space around a central body due to gravitational force.

Correct Answer: Conversion of ammonia to nitrites


Solution : The correct option is Conversion of ammonia to nitrites.

Nitrification is the process by which some bacteria in the soil convert ammonia (NH3) and ammonium ions (NH4+) to nitrite (NO2-) and ultimately to nitrate (NO3-). It is an important phase in the nitrogen cycle that contributes significantly to the availability of nitrogen to plants for growth. Nitrification is caused by two kinds of bacteria: Ammonia-Oxidizing Bacteria (AOB): AOB converts ammonia (NH3) to nitrite (NO2-). NOB: Nitrite-Oxidizing Bacteria (NOB) convert nitrite (NO2-) to nitrate (NO3-). 
 

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