What Is Ammonium Chloride? Chemical Structure, Uses & Everyday Examples
A chemical compound is a compound which is formed from the atoms of different elements combined in a specific ratio. The various types of atoms are joined by chemical bonds. Every compound has a fixed ratio between the elements. The elements combine together so strongly that the compound behaves like one substance.
Chemical compounds can be in the form of liquid such as water, which is made from the atoms of hydrogen and oxygen sticking together. Chemical compounds can be in the form of solid such as sodium chloride which is made from the atoms of sodium and chlorine sticking together. Some chemical compounds are dangerous to use if they are not handled with proper safety measures. There are many chemical compounds, which we use in our daily life, and today we will talk about such a chemical Compound.
Overview of Ammonium Chloride
Ammonium chloride is an inorganic chemical compound. Ammonium Chloride is a white crystalline salt that is highly soluble in water. Ammonium Chloride is composed of ammonium and chloride ions. Ammonium Chloride is a colourless chemical compound. The nature of the solutions of ammonium chloride is mildly acidic. The other names of ammonium chloride are Sal ammoniac, Salmiac, Nushadir salt, Sal Armagnac, Salt Armoniack, Salmiak.
Sal ammoniac is a natural, mineralogical form of ammonium chloride. Sal ammoniac is generally formed on burning coal dumps from the condensation of coal-derived gases. Sal ammoniac is also found around some types of volcanic vents. Sal ammoniac is majorly used as fertiliser and a flavouring agent in some types of liquor. Sal ammoniac is the product from the reaction of hydrochloric acid and ammonia.
Structure of Ammonium Chloride
The Structure of NH4Cl or Ammonium Chloride is represented as follows.
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Properties of Ammonium Chloride
Let us look at the properties of Ammonium Chloride
Production of Ammonium Chloride
Ammonium Chloride is the product of the Solvay process. Apart from the Ammonium chloride, the sodium carbonate is another product of the Solvay process.
\[ CO_{2} + 2 NH_{3} + 2NaCl + H_{2}O \rightarrow 2NH_{4}Cl + Na_{2}CO_{3} \]
Usually, this method is used to minimise the release of ammonia from some industrial work. Commercially, ammonium chloride is prepared from the combination of ammonia (NH3) with either hydrogen chloride (gas) or hydrochloric acid.
\[ NH_{3} + HCl \rightarrow NH_{4}Cl \]
Reactions with Ammonium Chloride
To release ammonia gas, ammonium chloride reacts with the strong base.
\[ NH_{4}Cl + NaOH \rightarrow NH_{3} + NaCl + H_{2}O \]
Ammonium chloride reacts with the alkali metal carbonates at the increased temperature which gives the ammonia and alkali metal chloride.
\[ 2NH_{4}Cl + Na_{2}CO_{3} \rightarrow 2NaCl + CO_{2} + H_{2}O + 2NH_{3} \]
When heated, Ammonium chloride shows a neutral nature, but in reality, ammonium chloride decomposes into ammonia, and hydrogen chloride gas on the heat.
\[ NH_{4}Cl \rightarrow NH_{3} + HCl \]
The solution of ammonium chloride in water has a pH in the range of 4.6 to 6.0.
History of Ammonium Chloride
The ancient mention of the ammonium chloride was in 554 A.D. in China. There were two sources of ammonium chloride at the time. The first source was the vents of underground coal fires in Central Asia, specifically, in the Tian Shan Mountains. The second source of ammonium chloride was the fumaroles of the volcano Mount Taftan in southeastern Iran. The Ammonium chloride word is derived from the Iranian phrase anosh adur which means immortal fire. Ammonium chloride was transported at that time along the Silk Road eastwards to China and westwards to the Muslim lands and Europe. The Arabs of Egypt discovered ammonium chloride in 800 A.D. from the burning camel dung, and that source became an alternative source in Central Asia.
Application of Ammonium Chloride
Fertilisers
The main application of ammonium chloride is as a source of nitrogen in fertilisers. In Asia, in the crops of rice and wheat, Ammonium chloride is used as a fertiliser.
Metalwork
In preparing metals which are to be tin coated, galvanised or soldered, Ammonium chloride is used as a flux. Ammonium chloride works as a flux which cleans the surface of workpieces. Ammonium chloride is used as a flux in solder as well.
Medicine
Ammonium chloride is used in the field of medicine too. Ammonium chloride is used in cough medicines. Ammonium salts are useful to reduce nausea and vomiting. In the treatment of severe metabolic alkalosis, Ammonium chloride is used as a systemic acidifying agent. Ammonium chloride is useful in the oral acid loading test to diagnose distal renal tubular acidosis too.
Food
Ammonium chloride is used as a yeast nutrient in breadmaking and as an acidifier. In dark sweets called Salmiak, Ammonium chloride is used to spice up. Salmiak is a dark sweet which is popular in Nordic and other nearby countries. In baked cookies, ammonium chloride is used to bring the crisp texture. Ammonium chloride is called the Noshader in Iran, Tajikistan, India, Pakistan, and some Arab countries. In samosas and jalebi, ammonium chloride is used to improve the crispness.
In the Laboratory
To produce low temperatures in cooling baths, Ammonium chloride is used. As a buffer solution, ammonium chloride is used with ammonia. In palaeontology, the vapour of ammonium chloride is cemented on fossils; this stuff forms a white layer which can be easily removed and it is quite harmless.
Flotation
With the help of ammonium chloride solution, Giant squid and some other large species of squid maintain the neutral buoyancy in seawater because the density of the solution of Ammonium chloride is less than the density of seawater. The solution of ammonium chloride tastes like Salmiakki, and because of this unusual taste, giant squids feel un-attracted towards the human.
Other Applications
To reduce the clay swelling problems, ammonium chloride is used for 5% in aqueous solution. Ammonium chloride is used as an electrolyte in Zinc-Carbon batteries. Ammonium chloride is used in hair shampoo, and cleaning products too. Ammonium chloride is used as glue to attach two plywood. For dyeing, tanning, textile printing, and cotton clustering, ammonium chloride is used in textile and leather industries. In Leclanché cells, Ammonium Chloride was used in aqueous solution as an electrolyte in the start of the 20th century. Ammonium chloride is used in Iron which is used for clothes.
FAQs on Ammonium Chloride: Properties, Formula & Applications
1. What is ammonium chloride and what is its chemical formula?
Ammonium chloride is an inorganic compound that is a white crystalline salt. It is highly soluble in water, and its aqueous solution is mildly acidic. The chemical formula for ammonium chloride is NH₄Cl. It is formed from the reaction between a weak base, ammonia (NH₃), and a strong acid, hydrochloric acid (HCl).
2. What are the key physical properties of ammonium chloride?
Ammonium chloride exhibits several distinct physical properties that are important for its identification and application. These include:
Appearance: It is a white, crystalline solid at room temperature.
Odour: It is odourless.
Taste: It has a cooling, saline taste.
Solubility: It is highly soluble in water and its solubility increases with temperature. It is also soluble in glycerol and slightly soluble in alcohol.
Melting/Sublimation Point: Ammonium chloride sublimes at 340 °C (644 °F), meaning it turns directly from a solid to a gas upon heating.
Molar Mass: The molar mass of NH₄Cl is approximately 53.49 g/mol.
3. How is ammonium chloride prepared on an industrial scale?
Industrially, ammonium chloride is primarily produced as a by-product of the Solvay process, which is used to manufacture sodium carbonate (soda ash). In this process, ammonia reacts with carbon dioxide and a sodium chloride solution. It can also be manufactured by the direct reaction of ammonia gas (NH₃) with hydrogen chloride gas (HCl) or hydrochloric acid, which is a simple acid-base neutralisation reaction.
4. What are the most common applications and uses of ammonium chloride?
Ammonium chloride has a wide range of applications across various industries:
Fertilisers: It serves as a nitrogen source in fertilisers, especially for rice and wheat crops.
Metalwork: It is used as a flux in preparing metals for tin coating, galvanising, or soldering to clean the surface of metal oxides.
Dry Cell Batteries: It acts as an electrolyte in zinc-carbon batteries.
Medicine: It is used as an expectorant in cough syrups and as a systemic acidifying agent.
Food Industry: In some countries, it is used as a food additive (E510) and a flavouring agent, particularly in liquorice and salty snacks.
5. Why does heating ammonium chloride appear like sublimation but is actually a chemical decomposition?
Although the process appears to be sublimation (solid to gas), heating ammonium chloride causes a reversible chemical decomposition. At high temperatures (around 340 °C), the solid NH₄Cl breaks down into two gaseous products: ammonia (NH₃) and hydrogen chloride (HCl). When these hot gases cool down, they immediately react to reform solid ammonium chloride. This rapid recombination of gases back into a solid mimics the appearance of sublimation, but it involves a chemical change rather than just a physical phase change.
6. Why is an aqueous solution of ammonium chloride acidic?
An aqueous solution of ammonium chloride is acidic due to a process called salt hydrolysis. Ammonium chloride is a salt formed from a weak base (ammonium hydroxide, NH₄OH) and a strong acid (hydrochloric acid, HCl). When dissolved in water, the ammonium ion (NH₄⁺) reacts with water to produce hydronium ions (H₃O⁺) and ammonia (NH₃). The increase in the concentration of hydronium ions makes the solution acidic, typically with a pH between 4.6 and 6.0.
7. How does the acidic nature of ammonium chloride explain its use as a flux in soldering?
Ammonium chloride's effectiveness as a flux is directly related to its thermal decomposition and acidic properties. When heated during soldering, it decomposes into ammonia and hydrogen chloride gas. The hydrogen chloride (HCl) is a strong acid that reacts with the non-conductive, non-fusible metal oxides present on the surface of the metals being joined. This reaction cleans the surface by converting the oxides into volatile metal chlorides, allowing the molten solder to flow freely and form a strong, clean metallic bond.
8. Is ammonium chloride an ionic or covalent compound? Explain its bonding.
Ammonium chloride is an interesting compound that exhibits both ionic and covalent bonding. The primary bond is ionic, existing between the positively charged ammonium cation (NH₄⁺) and the negatively charged chloride anion (Cl⁻). However, within the ammonium cation itself, the four bonds between the central nitrogen atom and the four hydrogen atoms are polar covalent bonds.
9. What is the specific role of ammonium chloride in medicine?
In medicine, ammonium chloride has two primary functions:
Expectorant: It is used as an active ingredient in some cough syrups. It works by irritating the mucous membranes, which leads to the production of more fluid in the respiratory tract, making phlegm thinner and easier to cough up.
Systemic Acidifying Agent: It is used to treat patients with severe metabolic alkalosis, a condition where the body's pH is too high (alkaline). By administering ammonium chloride, the liver converts the ammonium ion to urea, releasing a proton (H⁺) that helps lower the blood pH back to a normal range.
10. What are the potential hazards associated with handling ammonium chloride?
While generally safe for its intended applications, ammonium chloride can pose some hazards. Direct contact can cause irritation to the skin, eyes, and respiratory system. Inhaling its dust or fumes (from heating) can lead to coughing and shortness of breath. Ingestion of large quantities can cause nausea, vomiting, and acidosis. Therefore, it is important to handle it with appropriate safety precautions, such as wearing gloves and eye protection in a well-ventilated area.
