NH4OH Ammonium Hydroxide - Formula, Properties, Uses, FAQs

Q: How does NH4OH work in chemistry?

The ammonia solution of water (NH 4 OH) is ammonium hydroxide. The compound, also known as ammonia or ammonia gas, is used as a cleaner as well as a fertilizer, plastic, and textile dye. There's a pungent-to-faint ammonia smell to this white, colourless liquid.

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

Ammonium Hydroxide (NH₄OH) is what?

In a water solution of ammonia, the formula NH₄OH is used. Ammonium hydroxide, ammonia water, ammonium hydroxide, ammonia liquor, aqueous ammonia, and many others are trademarks of this solution. Sometimes, NH₄OH is abbreviated as NH₃ _(aq).

Amount of NH4OH in a solution

A proton is donated to ammonia molecules by water molecules when they are dissolved in water. During this process, an ammonium cation (whose chemical formula is NH₄⁺) and a hydroxide ion (OH )) are formed. Equilibrium reactions can be represented as follows.

NH₃ + H₂O ⇌ NH₄⁺ + OH^–

When ammonia is dissolved in water at a concentration of 1M, it converts to ammonium cation at 0.42%.

The presence of H⁺ can fully ionize a solid base. The oppositely charged side of OH^- will be completely ionized to form water and complementary sodium from its counterpart. Take the example of NaOH dissolving in water as our solid base.

When H⁺ ions (originating from OH^– and H⁺ in water) are present, NaOH is readily formed by H₂O and NaOH because the positively charged sodium interacts with the negatively charged OH^– from water and the negatively charged OH^- from the Na⁺. OH^–.

Assuming ammonium hydroxide as the product, we'd get NH₄⁺OH^– + H₂O. It is important to remember that each reaction has the same reactants as it has its products.

Also read -

This Story also Contains

Ammonium Hydroxide (NH4OH) is what?
Ammonium Hydroxide (NH4OH): Properties
Hydrogen Ammonium Uses

Ammonium Hydroxide in Saturated Solutions

Temperature increases decrease ammonia solubility in water. Ammonia behaves in much the same way as other gases. Water containing dissolved ammonia exhibits a decreasing density as its concentration increases.

Assuming a solution of saturated ammonium hydroxide with a density of 288.75 K, 0.88 grams per mole is equal to one mole. Approximately 35.6% of the mass of this saturated ammonium hydroxide solution is ammonia, tracing to 308 grams per liter of saturated ammonium hydroxide solution.

Occurrence

By dissolving ammonia inside water, ammonium hydroxide is formed. It is still natural for this to happen.

Preparation

It is mainly made by hydrogen reacting directly with nitrogen, which is catalyzed by iron. In order to make ammonium hydroxide, the resulting ammonia is added to water.

Physical Properties

A colorless liquid with a pungent smell, ammonium hydroxide is colorless. The density of ammonium hydroxide is 0.91 g/mL-1. The melting point is -57.5oC and it has a boiling point of 37oC. It is highly miscible with water.

Properties of chemicals

Water partially dissociates the ammonium ion and the hydroxide ion of ammonium hydroxide, maintaining equilibrium. Furthermore, it has a low resistance to oxidation:

NH₄OH + H₂O ⇌ NH₄⁺ + OH⁻

As a result of the ion OH^-in equilibrium, the pH value of any solution can be maximized to maintain the basicity level.

Related Topics link,

Ammonium Hydroxide (NH₄OH): Properties

In its standard state, NH₄OH has the following properties:

A mole of NH₄OH weighs 35.04 grams.

In its liquid state, it appears colorless.

It is highly pungent and has a "fishy" smell.

In a 25% volume/weight solution, the density is 0.91 g/cc. The density of a 35% water/waste solution is 0.88 grams/cubic centimeter.

The melting point and boiling point of ammonium hydroxide 25 % mass fraction are 215.7 K and 310.8 K, respectively

-80 Kilojoules per mole is its enthalpy of formation standard.

NCERT Chemistry Notes:

Hydrogen Ammonium Uses

Industrial and laboratory applications of ammonia water are numerous. Ammonia solutions can be used for the following five purposes.

Ammonium hydroxide solution is used to manufacture chemical fertilizers. They can be dissolved in water or used as salts in these fertilizers.

Nitrogen-containing organic and inorganic chemicals are also produced with ammonium hydroxide. The chemical is used in the production of nitric acid.

Window cleaning liquids use NH₄OH solutions containing 1-3%. Directly sold as a cleaning agent is an ammonia solution in water (scented or plain).

The production of chloramine with ammonia can be used as a good disinfectant. While still water, it remains active over a longer period than chlorine.

An ammonium hydroxide solution can be sealed over wood that contains tannic acid to give it a dark stained appearance. As a result, furniture darkening is achieved with ammonium hydroxide solution.

Read more :

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

Hazards of ammonium hydroxide

Affected people may become ill in the event of being exposed to ammonium hydroxide (corrosive, irritant, permeator), if they come in contact with their eyes (irritant), if they swallow it, etc. There is no corrosion in the eyes. Lungs are not corroded by this product. To protect your eyes, mouth, and respiratory system, avoid using liquids or spray mists close to them.

In contact with the skin, ammonium hydrate will burn. Extreme The spray mist may cause extreme inflammatory reactions in the respiratory system, including coughing, choking, or shortness of breath. Ver-exposure will lead to death. Inflammation of the eyes is marked by redness, swelling, and scratching. Inflammation of the skin is marked by swelling, scaling, reddening, or, rarely, blistering.

The skin should be washed with water as soon as possible, for at least 15 minutes, after being touched. The irritation on the face should be soothed with an emollient. Prior to reusing clothing, hot water should be used to disinfect it. Before replacing your shoes, make sure they are clean. Medical attention should be sought immediately.

Make sure the patient is evacuated immediately to secure clothes that are loosely fitting, such as shirts, scarves, belts, and waistbands. In case of difficulty breathing, use oxygen. You should perform mouth-to-mouth resuscitation on the patient if he or she is not alive.

Whenever a poisonous, contagious, or corrosive substance is inhaled by a person delivering resuscitation assistance, this situation can be extremely dangerous. Make sure you get medical attention.

Also check-

Frequently Asked Questions (FAQs)

1. How does NH4OH work in chemistry?

The ammonia solution of water (NH₄OH) is ammonium hydroxide. The compound, also known as ammonia or ammonia gas, is used as a cleaner as well as a fertilizer, plastic, and textile dye. There's a pungent-to-faint ammonia smell to this white, colourless liquid.

2. What is the health risk of ammonium hydroxide?

Intense skin irritation and burns can occur when ammonium hydroxide is in contact with the skin. Depending on how much is ingested, it may cause diarrhoea, nausea, gastric pain, and in severe cases, perforation, central nervous system agitation, shock, seizures, and pulmonary oedema.

3. How do ammonium hydroxide and ammonia differ?

An ammonium hydroxide in water is used for household purposes. Their main difference is that ammonia does not contain water while ammonia hydroxide does. The combination of ammonia and water is called ammonium hydroxide. As its formula NH₃(aq) implies, it is not very ammonia-rich.

4. What is the corrosive nature of ammonium hydroxide?

The alkalinity and corrosion properties of ammonia make it a desirable chemical compound. The caustic ammonium hydroxide solution of ammonia gas and water is readily soluble. Gases such as ammonia are easily compressed and form a clear liquid under pressure. Steel tanks are typically used to transport solid ammonia.

5. Ammonium hydroxide solution: How do you make it?

Hydrogen peroxide preparation. By saturating water with ammonia gas, ammonium hydroxide is formed. An empty gas washing bottle is used to collect any solid particles that are mechanically transported from the flask and then to collect the ammonia gas transmitted directly from the flask.

6. Aqueous ammonia ammonium hydroxide is why it is called that?

Despite the fact that both methods of contrast demonstrate that the solution contains more acidic ammonia (and water) molecules than ammonium and hydroxide ions, these solutions are more specifically known as aqueous ammonia, not ammonium hydroxide.

7. Ammonia solution has what pH?

Ammonia is a compound made up of two nitrogen ions, one of which is negatively charged, and three sodium ions, one of which is positively charged. Around 11 is the pH of normal ammonia.

8. Ammonium hydroxide is how strong?

By releasing ammonia gas from the solution, ammonium hydroxide emits a pungent, suffocating odour. There is a wide range of concentrations in ammonium hydroxide solutions, from less than one percent ammonia to around 35 percent ammonia.

9. What is the chemical formula of ammonium hydroxide?

The chemical formula of ammonium hydroxide is NH4OH. However, it's important to note that this is a simplified representation. In reality, ammonium hydroxide exists as a solution of ammonia (NH3) in water, forming an equilibrium with ammonium (NH4+) and hydroxide (OH-) ions.

10. What is the difference between aqueous ammonia and ammonium hydroxide?

There is no fundamental difference between aqueous ammonia and ammonium hydroxide. Both terms refer to a solution of ammonia (NH3) in water. The term "ammonium hydroxide" emphasizes the equilibrium between ammonia, water, ammonium ions, and hydroxide ions, while "aqueous ammonia" simply indicates ammonia dissolved in water.

11. What is the role of hydrogen bonding in the high solubility of ammonia in water?

Hydrogen bonding plays a crucial role in the high solubility of ammonia in water. The lone pair of electrons on the nitrogen atom in ammonia can form hydrogen bonds with the hydrogen atoms of water molecules. This strong interaction between ammonia and water molecules allows for a high degree of solubility.

12. How does ammonium hydroxide behave differently from ammonia gas?

While ammonia gas (NH3) is a base, it cannot directly donate hydroxide ions. Ammonium hydroxide, being a solution of ammonia in water, can provide hydroxide ions through the reaction of ammonia with water. This makes ammonium hydroxide more reactive as a base in aqueous solutions compared to ammonia gas.

13. What is the significance of the ammonium-ammonia equilibrium in ammonium hydroxide solutions?

The ammonium-ammonia equilibrium (NH4+ ⇌ NH3 + H+) is crucial in ammonium hydroxide solutions. This equilibrium determines the pH of the solution and its behavior as a weak base. It also allows the solution to act as a buffer, resisting pH changes when small amounts of acid or base are added.

14. Why is ammonium hydroxide considered a weak base?

Ammonium hydroxide is considered a weak base because it only partially dissociates in water. The ammonia (NH3) in the solution accepts a proton from water to form ammonium (NH4+) and hydroxide (OH-) ions, but this process is reversible and doesn't go to completion.

15. How does the pH of ammonium hydroxide compare to that of strong bases?

The pH of ammonium hydroxide is lower than that of strong bases at the same concentration. While strong bases like sodium hydroxide (NaOH) completely dissociate in water, ammonium hydroxide only partially dissociates, resulting in a lower concentration of hydroxide ions and thus a lower pH.

16. How does ammonium hydroxide conduct electricity?

Ammonium hydroxide conducts electricity due to the presence of ions in solution. When ammonia dissolves in water, it forms ammonium (NH4+) and hydroxide (OH-) ions. These ions can carry electrical charge, allowing the solution to conduct electricity. However, as a weak electrolyte, its conductivity is lower than that of strong bases.

17. What is the Brønsted-Lowry definition of ammonium hydroxide?

According to the Brønsted-Lowry theory, ammonium hydroxide acts as a base by accepting a proton (H+) from water. The ammonia (NH3) in the solution is the actual Brønsted-Lowry base, forming the conjugate acid ammonium (NH4+) when it accepts a proton.

18. How does temperature affect the solubility of ammonia in water?

The solubility of ammonia in water decreases as temperature increases. This is because the dissolution of ammonia in water is an exothermic process. According to Le Chatelier's principle, increasing the temperature shifts the equilibrium towards the reactants, reducing the amount of dissolved ammonia.

19. What is the principle behind the use of ammonium hydroxide in qualitative analysis?

Ammonium hydroxide is used in qualitative analysis due to its ability to form complex ions with certain metal cations. It can act as a ligand, coordinating with metal ions to form soluble complex ions. This property is useful in separating and identifying different metal ions in a mixture, as some metals form complexes while others precipitate as hydroxides.

20. How does ammonium hydroxide interact with transition metal ions?

Ammonium hydroxide can act as a ligand for many transition metal ions, forming complex ions. The ammonia molecules in the solution can coordinate with metal ions, replacing water molecules in their hydration sphere. This can lead to color changes and the formation of soluble complex ions, which is useful in qualitative analysis and some industrial processes.

21. What is the role of ammonium hydroxide in the nitrogen cycle?

Ammonium hydroxide plays a role in the nitrogen cycle primarily through its ammonia content. In soil, ammonium ions (NH4+) from ammonium hydroxide can be converted to nitrates by nitrifying bacteria, making nitrogen available to plants. However, excessive use can lead to soil alkalinization and potential environmental issues.

22. How does ammonium hydroxide participate in acid-base titrations?

In acid-base titrations, ammonium hydroxide acts as a weak base. When titrated with a strong acid, it undergoes neutralization, forming ammonium salts. The titration curve for ammonium hydroxide is different from that of a strong base, showing a more gradual change in pH near the equivalence point due to its weak base nature.

23. How does the presence of ammonium hydroxide affect the solubility of metal hydroxides?

The presence of ammonium hydroxide can affect the solubility of metal hydroxides in two ways:

24. How does the concentration of ammonium hydroxide affect its properties?

The concentration of ammonium hydroxide significantly affects its properties. As concentration increases:

25. What is the buffer capacity of ammonium hydroxide?

Ammonium hydroxide has a buffer capacity due to the presence of both a weak base (NH3) and its conjugate acid (NH4+) in solution. This system can resist changes in pH when small amounts of acid or base are added. The buffer capacity is highest when the concentrations of NH3 and NH4+ are equal, which occurs at a pH equal to the pKa of ammonium (about 9.25).

26. What is the mechanism of the cleaning action of ammonium hydroxide?

Ammonium hydroxide's cleaning action is based on several mechanisms:

27. How does ammonium hydroxide contribute to the Kjeldahl method for nitrogen determination?

In the Kjeldahl method, ammonium hydroxide plays a crucial role in the final step. After the organic nitrogen in a sample is converted to ammonium sulfate, a strong base (usually sodium hydroxide) is added to convert ammonium to ammonia. This ammonia is then distilled into a known amount of boric acid solution. The amount of ammonia (and thus nitrogen) is determined by titrating the boric acid solution with a standard acid.

28. What safety precautions should be taken when handling ammonium hydroxide?

When handling ammonium hydroxide, several safety precautions are necessary:

29. How does the concept of Lewis acids and bases apply to ammonium hydroxide?

In terms of Lewis acid-base theory, the ammonia (NH3) in ammonium hydroxide acts as a Lewis base. It has a lone pair of electrons that it can donate to form a coordinate covalent bond. This allows it to react with Lewis acids (electron pair acceptors) such as metal ions, forming complex ions. The hydroxide ion (OH-) present in the solution can also act as a Lewis base.

30. What is the relationship between the pKa of ammonium and the pH of ammonium hydroxide solutions?

The pKa of ammonium (NH4+) is about 9.25. This value is crucial in determining the pH of ammonium hydroxide solutions. At a pH equal to the pKa, the concentrations of NH3 and NH4+ are equal. In a typical ammonium hydroxide solution, the pH is usually between 11-12, which means there's more NH3 than NH4+. The relationship between pKa and pH is described by the Henderson-Hasselbalch equation: pH = pKa + log([NH3]/[NH4+]).

31. How does ammonium hydroxide participate in precipitation reactions?

Ammonium hydroxide can participate in precipitation reactions in two ways:

32. What is the principle behind using ammonium hydroxide in blueprint making?

In blueprint making, ammonium hydroxide is used in the development process. The blueprint paper is coated with a light-sensitive iron compound. After exposure to light, the paper is treated with ammonium hydroxide. The ammonia reacts with the iron compound, turning the exposed areas blue. This process is based on the ability of ammonia to form complex ions with iron, resulting in the characteristic blue color.

33. How does ammonium hydroxide affect the pH of soil when used as a fertilizer?

When used as a fertilizer, ammonium hydroxide can initially increase soil pH due to its basic nature. However, over time, as microorganisms in the soil convert ammonium (NH4+) to nitrate (NO3-), the soil pH can decrease. This process, called nitrification, releases hydrogen ions, potentially leading to soil acidification if used excessively or without proper management.

34. What is the role of ammonium hydroxide in the production of synthetic fibers?

Ammonium hydroxide plays several roles in the production of synthetic fibers:

35. How does the presence of ammonium hydroxide affect the solubility of organic compounds?

Ammonium hydroxide can affect the solubility of organic compounds in several ways:

36. What is the principle behind using ammonium hydroxide in leather tanning?

In leather tanning, ammonium hydroxide is used in the deliming process. After the hides are treated with lime to remove hair and open up the fiber structure, ammonium hydroxide is used to neutralize the remaining lime. The ammonium ions react with calcium hydroxide to form soluble calcium salts, which can be washed away. This process helps to prepare the leather for further treatment and ensures even penetration of tanning agents.

37. How does ammonium hydroxide contribute to the Ostwald process for nitric acid production?

In the Ostwald process for nitric acid production, ammonium hydroxide isn't directly used, but ammonia (which is the key component of ammonium hydroxide) is crucial. The process involves:

38. What is the role of ammonium hydroxide in the extraction of certain metals from their ores?

Ammonium hydroxide plays a significant role in the extraction of some metals from their ores, particularly copper and nickel. This process, known as ammoniacal leaching, involves:

39. How does ammonium hydroxide affect the solubility of gases in water?

Ammonium hydroxide can affect the solubility of gases in water in several ways:

40. What is the principle behind using ammonium hydroxide in dyeing processes?

Ammonium hydroxide is used in dyeing processes for several reasons:

41. How does ammonium hydroxide interact with carbon dioxide in aqueous solutions?

When carbon dioxide dissolves in an ammonium hydroxide solution, several reactions occur:

42. What is the significance of ammonium hydroxide in the production of certain pharmaceuticals?

Ammonium hydroxide plays several roles in pharmaceutical production:

43. How does ammonium hydroxide contribute to the weathering of rocks and minerals?

Ammonium hydroxide can contribute to rock and mineral weathering in several ways: