Preparation And Properties Of Ammonia

Q: 1. What is the formula for ammonia as a chemical formula?

Solution: Chemical Formula: The chemical formula of ammonia is NH₃. Structure: That means one nitrogen atom is attached to three hydrogen atoms. Molecular Geometry: The ammonia molecule is trigonal pyramidal because a lone pair of electrons on nitrogen pushes the bond angles to less than 109.5-degree values, namely ~ 107 degrees.

Q: 2. What is the industrial process for the preparation of ammonia?

Solution: Haber-Bosch Process: The industrial preparation of ammonia takes place via the Haber-Bosch process. Raw Materials: This is the combination of nitrogen gas and hydrogen gas. Catalyst and Conditions: It is done in the presence of an iron catalyst and under high pressure of 150-200 atmospheres and high temperature of 400-500°C. Chemical Reaction : The balanced chemical equation says: N 2 (g) + 3H 2 (g) → 2NH 3 (g)

Q: 3. What are the main uses of ammonia?

Answer: Fertilizers: It manufactures nitrogenous fertilizers like urea, ammonium nitrate, and ammonium sulfate that act as growth fertilizers in plants. Refrigeration: Given the fact that it is energy-efficient, it gets applied as a refrigerant for industrial refrigeration systems; this therefore records minimal environmental cost as compared to that by CFCs in similar appliances. Household Cleaners: There is a line of household cleaners that contain ammonia, which is essential in staining and removal of grease. Industrial Applications: The major uses of Ammonia are in the production of explosives, synthetic fibers, plastics, and other chemicals.

Q: 5. What are the ecological problems associated with ammonia?

Solution: Water Pollution: Runoffs of ammonia from agricultural fields along with rainwater may act as sources of contamination of water. It includes the excessive growth of algae in the water bodies; when this algae gets decomposed, it consumes oxygen and thus hampers aquatic life. Air Pollution: Emits ammonia into the atmosphere, which can react to form particulate matter by decreasing air quality, hence increasing respiratory botheration in humans and animals. Soil Acidity: Overdosage in applying ammonia-based fertilizers acidifies the soils. By doing so, it contends with its very health leading to problems associated with productivity in agricultural processes. Ecosystem Disruption: Due to the impact of ammonia emissions on the nutrient balance of ecosystems, loss of biodiversity will occur and result in losses to some plant and animal species.

Preparation And Properties Of Ammonia

Edited By Shivani Poonia | Updated on Jul 02, 2025 06:40 PM IST

Imagine entering the kitchen and opening one of the bottles with the household cleaner. One will smell a strong smell with a bad odor. Most likely, Ammonia is going to be the compound. For sure, this is one of those compounds which significantly shapes our daily lives. Of course not only as a household cleaning reagent. Ammonia finds its invaluable application in agriculture and industry. It is applied in fertilizers for food, and in a wide range of industrial processes

This Story also Contains

Ammonia
Preparation Methods
Summary

Preparation And Properties Of Ammonia

Ammonia

Ammonia is a colorless gas, and it has a typical pungent smell. Ammonias are one nitrogen atom bonded with three hydrogen atoms chemically, NH3. This is a very simple and very interesting molecule because of its polarity and the possibility of hydrogen bonding. The independence and corollaries of the very same polar nature and hydrogen bonding make ammonia highly soluble in water by forming ammonium hydroxide on dissolution, NH₄OH. This thereby made possible ground for the remainder of the work on its applications and preparation methods because it brings into play knowledge of the overall chemical structure and properties of ammonia.

Preparation Methods

The Haber-Bosch process offers a significant method of preparation for ammonia and was developed in the early twentieth century, whereby it greatly revolutionized agriculture and industry. The process maintained for the same is basically the direct combination of nitrogen in the air with high pressure and temperature in the presence of an iron catalyst. This reaction is made use of a well-balanced chemical equation as follows:
N₂(g) + 3H₂(g) → 2NH₃(g)
Another process involves heating ammonium salts; for instance, ammonium chloride, upon reaction with a strong base, such as calcium hydroxide, in another to produce the ammonia gas. All these different processes indicate just how urgent the production of ammonia is for the realized ends of industry and for chemical purposes; thus, they only amount to just how much chemistry and engineering meet.

Preparation

Ammonia is present in small quantities in air and soil where it is formed by the decay of nitrogenous organic matter e.g., urea.

$\mathrm{NH}_2 \mathrm{CONH}_2+2 \mathrm{H}_2 \mathrm{O} \rightarrow\left(\mathrm{NH}_4\right)_2 \mathrm{CO}_3 \rightleftharpoons 2 \mathrm{NH}_3+\mathrm{H}_2 \mathrm{O}+\mathrm{CO}_2$

NH2CONH2+2H2O→(NH4)2CO3⇌2NH3+H2O+CO2

On a small scale, ammonia is obtained from ammonium salts which decompose when treated with caustic soda or calcium hydroxide.

$\begin{aligned} & 2 \mathrm{NH}_4 \mathrm{Cl}+\mathrm{Ca}(\mathrm{OH})_2 \rightarrow 2 \mathrm{NH}_3+2 \mathrm{H}_2 \mathrm{O}+\mathrm{CaCl}_2 \\ & \left(\mathrm{NH}_4\right)_2 \mathrm{SO}_4+2 \mathrm{NaOH} \rightarrow 2 \mathrm{NH}_3+2 \mathrm{H}_2 \mathrm{O}+\mathrm{Na}_2 \mathrm{SO}_4\end{aligned}$

2NH4Cl+Ca(OH)2→2NH3+2H2O+CaCl2(NH4)2SO4+2NaOH→2NH3+2H2O+Na2SO4

On a large scale, ammonia is manufactured by Haber’s process.

N₂(g) + 3H₂(g) → 2NH₃(g)

In accordance with Le Chatelier’s principle, high pressure would favor the formation of ammonia. The optimum conditions for the production of ammonia are a pressure of 200 × 10⁵ Pa (about 200 atm), a temperature of ~ 700 K, and the use of a catalyst such as iron oxide with small amounts of K₂O and Al₂O₃ to increase the rate of attainment of equilibrium. The flow chart for the production of ammonia is shown in the figure given below. Earlier, iron was used as a catalyst with molybdenum as a promoter.

Properties

Ammonia is a colorless gas with a pungent odor. Its freezing and boiling points are 198.4 and 239.7 K respectively. In the solid and liquid states, it is associated through hydrogen bonds as in the case of water and that accounts for its higher melting and boiling points than expected on the basis of its molecular mass. The ammonia molecule is trigonal pyramidal with the nitrogen atom at the apex. It has three bond pairs and one lone pair of electrons as shown in the structure. Ammonia gas is highly soluble in water. Its aqueous solution is weakly basic due to the formation of OH^–ions.

NH3( g)+H2O(l)⇌NH4+(aq)+OH−(aq)

$\mathrm{NH}_3(\mathrm{~g})+\mathrm{H}_2 \mathrm{O}(\mathrm{l}) \rightleftharpoons \mathrm{NH}_4^{+}(\mathrm{aq})+\mathrm{OH}^{-}(\mathrm{aq})$

It forms ammonium salts with acids, e.g., NH₄Cl, (NH₄)₂SO₄, etc. As a weak base, it precipitates the hydroxides (hydrated oxides in the case of some metals) of many metals from their salt solutions. For example,

$\begin{aligned} & \mathrm{ZnSO}_4(\mathrm{aq})+2 \mathrm{NH}_4 \mathrm{OH}(\mathrm{aq}) \rightarrow \mathrm{Zn}(\mathrm{OH})_2(\mathrm{~s})+\left(\mathrm{NH}_4\right)_2 \mathrm{SO}_4(\mathrm{aq}) \\ & \mathrm{FeCl}_3(\mathrm{aq})+\mathrm{NH}_4 \mathrm{OH}(\mathrm{aq}) \rightarrow \mathrm{Fe}_2 \mathrm{O}_3 \cdot \mathrm{xH}_2 \mathrm{O}(\mathrm{s})+\mathrm{NH}_4 \mathrm{Cl}(\mathrm{aq})\end{aligned}$

The presence of a lone pair of electrons on the nitrogen atom of the ammonia molecule makes it a Lewis base. It donates the electron pair and forms a linkage with metal ions and the formation of such complex compounds finds applications in the detection of metal ions such as Cu²⁺, and Ag⁺.

Uses

Ammonia is used to produce various nitrogenous fertilizers (ammonium nitrate, urea, ammonium phosphate, and ammonium sulfate)
It is used in the manufacture of some inorganic nitrogen compounds, the most
important one being nitric acid.
Liquid ammonia is also used as a refrigerant.

NEET Highest Scoring Chapters & Topics

This ebook serves as a valuable study guide for NEET exams, specifically designed to assist students in light of recent changes and the removal of certain topics from the NEET exam.

Download EBook

Relevance and Applications

Any other major application of ammonia involves agriculture. It is used in the production of ammonia-based fertilizers such as urea, ammonium nitrate, and ammonium sulfate. These fertilizers are in high demand, as they are supposed to improve the yields of crops in order to be guaranteed bountiful harvests for food production. Applications of ammonia occur in the industrial sector concerned with the production of nitric acid. It also finds application in refrigerating systems as ammonia absorbs heat well.

This small molecule of ammonia contains a large number of hydrogen bondings. Research for its different applications thus falls under the realms of inorganic and physical chemistry. It also has a very major role in the nitrogen cycle and its related impacts on the environment, more so around its release from agricultural activities, and thereafter what impacts it has caused in turn, for example, on ecosystems. These many uses underpin the importance to which application and study are placed in the science of ammonia.

Summary

From being merely one of the very pungent elements that make for household cleaners to an immense service given globally and industrially is ammonia. It is critical to perform discussions on the preparation of ammonia via the Haber-Bosch process and the reaction of ammonium salts with a base. From fertilizers, through industry, to research in academics, such are its endless applications. A foothold of information about the preparation and properties of ammonia will outline the chemical character of the compound and set forth quite cogent arguments for the utility value in a number of various fields.

Frequently Asked Questions (FAQs)

1. 1. What is the formula for ammonia as a chemical formula?

Solution:
Chemical Formula: The chemical formula of ammonia is NH₃.
Structure: That means one nitrogen atom is attached to three hydrogen atoms.
Molecular Geometry: The ammonia molecule is trigonal pyramidal because a lone pair of electrons on nitrogen pushes the bond angles to less than 109.5-degree values, namely ~ 107 degrees.

2. 2. What is the industrial process for the preparation of ammonia?

Solution:
Haber-Bosch Process: The industrial preparation of ammonia takes place via the Haber-Bosch process.
Raw Materials: This is the combination of nitrogen gas and hydrogen gas.
Catalyst and Conditions: It is done in the presence of an iron catalyst and under high pressure of 150-200 atmospheres and high temperature of 400-500°C.
Chemical Reaction: The balanced chemical equation says:
N₂(g) + 3H₂(g) → 2NH₃(g)

3. 3. What are the main uses of ammonia?

Answer:
Fertilizers: It manufactures nitrogenous fertilizers like urea, ammonium nitrate, and ammonium sulfate that act as growth fertilizers in plants.
Refrigeration: Given the fact that it is energy-efficient, it gets applied as a refrigerant for industrial refrigeration systems; this therefore records minimal environmental cost as compared to that by CFCs in similar appliances.
Household Cleaners: There is a line of household cleaners that contain ammonia, which is essential in staining and removal of grease.
Industrial Applications: The major uses of Ammonia are in the production of explosives, synthetic fibers, plastics, and other chemicals.

4. 4. Role of Ammonia in Agriculture: Answer:

The Role of Ammonia in Producing Fertilizers: Since ammonia forms a crucial part of these fertilizers as the primary source of nitrogen to be applied on the plants alongside those very fertilizers that maximize crop yield, it becomes very important in agriculture.
Plant Nutrition: Nitrogen is on the list of very essential plant nutrients. By this application, the ammonia-based fertilizer provides nitrogen to the plants in a form they can absorb and process.
Food Production: The application of ammonia in the form of fertilizers maintains the food production process so that more and more people may be fed in the world.

5. 5. What are the ecological problems associated with ammonia?

Solution:
Water Pollution: Runoffs of ammonia from agricultural fields along with rainwater may act as sources of contamination of water. It includes the excessive growth of algae in the water bodies; when this algae gets decomposed, it consumes oxygen and thus hampers aquatic life.
Air Pollution: Emits ammonia into the atmosphere, which can react to form particulate matter by decreasing air quality, hence increasing respiratory botheration in humans and animals.
Soil Acidity: Overdosage in applying ammonia-based fertilizers acidifies the soils. By doing so, it contends with its very health leading to problems associated with productivity in agricultural processes.
Ecosystem Disruption: Due to the impact of ammonia emissions on the nutrient balance of ecosystems, loss of biodiversity will occur and result in losses to some plant and animal species.

6. How does the structure of the ammonia molecule contribute to its properties?

The ammonia molecule has a pyramidal shape with the nitrogen atom at the apex and three hydrogen atoms at the base. This structure, along with the lone pair on the nitrogen, gives ammonia its polar nature and ability to form hydrogen bonds, contributing to properties like its high boiling point for its molecular weight and its solubility in water.

7. Why is ammonia considered a weak base?

Ammonia is considered a weak base because it only partially dissociates in water. When dissolved, it forms ammonium ions (NH₄⁺) and hydroxide ions (OH⁻), but this reaction doesn't go to completion. The equilibrium strongly favors the undissociated ammonia molecules, resulting in a relatively low concentration of hydroxide ions.

8. How does the lone pair of electrons on nitrogen affect ammonia's reactivity?

The lone pair of electrons on the nitrogen atom makes ammonia a good electron donor, allowing it to act as a Lewis base. This lone pair can form coordinate covalent bonds with metal ions, making ammonia an excellent ligand in complex ion formation. It also enables ammonia to participate in acid-base reactions by accepting protons.

9. How does ammonia's solubility in water compare to other gases, and why?

Ammonia is exceptionally soluble in water compared to most gases. At 20°C, about 700 volumes of ammonia gas can dissolve in one volume of water. This high solubility is due to ammonia's ability to form hydrogen bonds with water molecules and its reaction with water to form ammonium and hydroxide ions.

10. What is the significance of ammonia's dipole moment?

Ammonia's dipole moment is significant because it arises from the uneven distribution of electron density in the molecule. The nitrogen atom, being more electronegative, pulls electron density away from the hydrogen atoms. This polarity contributes to ammonia's ability to dissolve in polar solvents, form hydrogen bonds, and participate in various chemical reactions.

11. What is the Haber process and why is it important for ammonia production?

The Haber process is an industrial method for producing ammonia from nitrogen and hydrogen gases. It's important because it revolutionized the production of fertilizers, making large-scale food production possible. The process involves reacting nitrogen and hydrogen at high temperature and pressure over an iron catalyst.

12. Why is a catalyst used in the Haber process?

A catalyst is used in the Haber process to increase the rate of reaction between nitrogen and hydrogen. The iron catalyst lowers the activation energy, allowing the reaction to proceed more quickly at lower temperatures. This makes the process more efficient and economically viable on an industrial scale.

13. How does temperature affect the yield of ammonia in the Haber process?

Temperature has a complex effect on ammonia yield. Increasing temperature speeds up the reaction rate but decreases the equilibrium yield of ammonia because the reaction is exothermic. A compromise temperature of about 450°C is typically used to balance reaction rate and yield.

14. Why is high pressure favored in the Haber process?

High pressure is favored in the Haber process because it increases the yield of ammonia. According to Le Chatelier's principle, increasing pressure shifts the equilibrium towards the side with fewer gas molecules. In this case, that's the ammonia side (4 reactant molecules become 2 product molecules).

15. What is the role of nitrogen fixation in the ammonia production process?

Nitrogen fixation is the process of converting atmospheric nitrogen (N₂) into a form that can be used by living organisms. In ammonia production, nitrogen fixation occurs when N₂ is converted to NH₃. This is crucial because atmospheric nitrogen is otherwise unreactive due to its strong triple bond.

16. What is meant by the "fountain experiment" with ammonia, and what does it demonstrate?

The "fountain experiment" involves inverting a flask of ammonia gas over a container of water with a few drops of indicator. As the ammonia dissolves, it creates a partial vacuum, drawing water up into the flask and creating a "fountain" effect. The experiment demonstrates ammonia's high solubility in water and its basic nature, as shown by the color change of the indicator.

17. How does the boiling point of ammonia compare to similar molecules, and why?

Ammonia has a higher boiling point (-33.34°C) than one might expect for a molecule of its size, but lower than water (100°C). This is due to hydrogen bonding between ammonia molecules, which is stronger than typical intermolecular forces but weaker than the hydrogen bonding in water. The presence of only one lone pair (compared to two in water) results in weaker overall hydrogen bonding.

18. Why is ammonia often stored as a liquid under pressure?

Ammonia is often stored as a liquid under pressure because it allows for more compact storage and easier transport. At room temperature, ammonia is a gas, but it can be liquefied under moderate pressure. This liquid form is denser than the gas, allowing more ammonia to be stored in a given volume. When the pressure is released, the liquid ammonia quickly vaporizes, making it easy to use.

19. How does ammonia react with acids, and what is the product called?

Ammonia reacts with acids to form ammonium salts. In this reaction, ammonia acts as a base, accepting a proton from the acid. For example, when ammonia reacts with hydrochloric acid, it forms ammonium chloride:

20. What is the difference between anhydrous ammonia and aqueous ammonia?

Anhydrous ammonia refers to pure ammonia gas or liquid ammonia without water. Aqueous ammonia, also known as ammonium hydroxide, is a solution of ammonia dissolved in water. Anhydrous ammonia is more concentrated and reactive, while aqueous ammonia is easier to handle and less hazardous. The properties and uses of these two forms can differ significantly.

21. How does ammonia contribute to the nitrogen cycle in nature?

Ammonia plays a crucial role in the nitrogen cycle. It's produced naturally by the decomposition of organic matter and by nitrogen-fixing bacteria. Plants can absorb ammonia directly or after it's converted to nitrates by nitrifying bacteria. Animals excrete nitrogen mainly as urea, which is converted back to ammonia by bacteria. This cycle is essential for the movement of nitrogen through ecosystems.

22. Why is ammonia considered both a Brønsted-Lowry base and a Lewis base?

Ammonia is considered a Brønsted-Lowry base because it can accept a proton (H⁺) to form the ammonium ion (NH₄⁺). It's also a Lewis base because its lone pair of electrons can form a coordinate covalent bond with a Lewis acid (electron pair acceptor). This dual nature makes ammonia versatile in various chemical reactions and complex formations.

23. How does the shape of the ammonia molecule contribute to its polarity?

The ammonia molecule has a trigonal pyramidal shape with the nitrogen atom at the apex and the three hydrogen atoms forming the base of the pyramid. This geometry, combined with the difference in electronegativity between nitrogen and hydrogen, results in a net dipole moment. The lone pair on nitrogen pushes the hydrogen atoms slightly closer together, enhancing the molecule's polarity.

24. What safety precautions are necessary when handling ammonia?

Handling ammonia requires several safety precautions:

25. How does ammonia behave as a ligand in coordination compounds?

Ammonia acts as a monodentate ligand in coordination compounds. Its lone pair of electrons on the nitrogen atom can form a coordinate covalent bond with a metal ion. This ability makes ammonia an important ligand in many complex ions and coordination compounds, such as [Cu(NH₃)₄]²⁺ (tetraamminecopper(II) ion). The strength of the metal-ammonia bond can vary depending on the metal ion.

26. What is the significance of ammonia's autoionization in liquid ammonia?

Autoionization of liquid ammonia is similar to the autoionization of water. In liquid ammonia, a small fraction of molecules react with each other:

27. How does the reactivity of ammonia compare with other Group 15 hydrides?

Ammonia (NH₃) is generally more reactive than the heavier Group 15 hydrides like phosphine (PH₃) and arsine (AsH₃). This higher reactivity is due to several factors:

28. What is the role of ammonia in the production of nitric acid?

Ammonia is a key starting material in the industrial production of nitric acid through the Ostwald process. The steps involve:

29. How does the presence of ammonia affect the pH of water?

When ammonia dissolves in water, it increases the pH, making the solution basic. This occurs because ammonia acts as a weak base, accepting protons from water molecules to form ammonium ions (NH₄⁺) and hydroxide ions (OH⁻):

30. Why is ammonia used as a refrigerant, and what are its advantages and disadvantages?

Ammonia is used as a refrigerant due to several advantages:

31. How does ammonia participate in acid-base titrations?

Ammonia can participate in acid-base titrations as a weak base. When titrated with a strong acid like hydrochloric acid, ammonia accepts protons to form ammonium ions:

32. What is the significance of ammonia's critical temperature and pressure?

The critical temperature of ammonia is 132.4°C, and its critical pressure is 11.28 MPa. These values are significant because:

33. How does ammonia interact with transition metal ions to form complex ions?

Ammonia interacts with transition metal ions to form complex ions through its lone pair of electrons. The nitrogen atom in ammonia donates this lone pair to the metal ion, forming a coordinate covalent bond. This process can be represented as:

34. What is the role of ammonia in biological systems?

In biological systems, ammonia plays several important roles:

35. How does the electron configuration of nitrogen contribute to the properties of ammonia?

The electron configuration of nitrogen (1s² 2s² 2p³) directly contributes to ammonia's properties:

36. What is the relationship between ammonia and amines?

Ammonia is the simplest member of the amine family. Amines can be considered derivatives of ammonia where one or more hydrogen atoms are replaced by alkyl or aryl groups. The relationship includes:

37. How does ammonia behave in non-aqueous solvents?

In non-aqueous solvents, ammonia's behavior can differ significantly from its behavior in water:

38. What is the importance of ammonia in the production of fertilizers?

Ammonia is crucial in fertilizer production for several reasons: