Salt is the most used condiment worldwide. Its other forms include baking soda, Epsom salt, and sea salt, to name a few. If you are wondering how is salt made? The combination consists of an anion from an acid and a cation from a base. The anion is a negatively charged ion. The cation is a positively charged ion. In common salt, sodium is the cation (Na+) and chloride (Cl-) is the anion. The chemical formula of salt is NaCl. Other types of salt combinations are magnesium chloride and potassium chloride. The chemical combination of Epsom Salt is magnesium sulphate (MgSO4). Baking soda is sodium hydrogen carbonate (NaHCO3).
Salts are chemical compounds. They form when an acid and a base react in a neutralisation reaction. Salts are ideal electrolytes. In their molten form, most salts dissolve into negatively and positively charged ions. Salts can form crystal structures. They are solid structures made of repeating patterns of ions. For instance, table salt forms cubic crystals and Epsom salt forms needle-like crystals. The chemical composition has a significant impact on the crystal structure. Furthermore, table salt is water-soluble, with a melting point of 801°C, and Epsom salt's melting point is 200°C.
We call the reaction of salt with water hydrolysis. It reverses the neutralisation reaction. In hydrolysis, the salt dissociates to form ions. The extent depends on the salt's solubility product.
| Property | Acidic Salt | Basic Salt | Neutral Salt |
|---|---|---|---|
| pH of Solution | < 7 (acidic) | > 7 (basic) | = 7 (neutral) |
| Formation | Strong acid + weak base | Strong base + weak acid | Strong acid + strong base |
| Effect on pH | Lowers pH, makes the solution acidic | Increases pH, makes the solution basic | No significant effect on pH |
| Ion Produced | Produces H⁺ ions | Produces OH⁻ ions | No significant production of H⁺ or OH⁻ |
| Example | NH₄Cl (Ammonium chloride) | Na₂CO₃ (Sodium carbonate) | NaCl (Sodium chloride) |
| Hydrolysis | Cation hydrolyzes, releasing H⁺ ions | Anion hydrolyzes, releasing OH⁻ ions | Neither cation nor anion hydrolyzes |
| Conjugate Acid/Base | Conjugate acid of a weak base (e.g., NH₄⁺) | Conjugate base of a weak acid (e.g., CO₃²⁻) | Neither conjugate acid nor conjugate base significantly reacts |
| Common Examples | NH₄Cl, FeSO₄, AlCl₃ | Na₂CO₃, Na₂SO₃, Na₄[Fe(CN)₆] | NaCl, KCl, HCl, KNO₃ |
| Chemical Nature of Anion | Anion from weak acid (e.g., Cl⁻ from HCl) | Anion from weak acid (e.g., CO₃²⁻ from H₂CO₃) | Anion from strong acid (e.g., Cl⁻ from HCl) |
| Chemical Nature of Cation | Cation from weak base (e.g., NH₄⁺ from NH₃) | Cation from strong base (e.g., Na⁺ from NaOH) | Cation from strong base (e.g., Na⁺ from NaOH) |
Salts are chemical compounds. They have unique properties and many uses in everyday life and various industries. The history of salts dates back as far as 6050 BCE. In Egypt, people used them to preserve Mummies. For the Phoenicians and their Mediterranean empire, it was a key trade commodity. We use salts to remove trace amounts of water from aviation fuel. You can find many more applications of salt besides sprinkling a pinch in your meals.
Salts such as ammonium sulfate and potassium chloride are used as fertilizers to provide essential nutrients to plants.
Single salts consist of monoatomic ions (e.g., NaCl), while polyatomic salts contain polyatomic ions like sulfate (SO?²?) or nitrate (NO??).
Adding salt lowers the freezing point (freezing point depression) and raises the boiling point (boiling point elevation) of water.
Salts like sodium chloride are used in water softeners to replace calcium and magnesium ions, which cause water hardness.
A salt is formed from the reaction of an acid and a base, while an ester is formed from the reaction of an acid and an alcohol.
Salts help regulate osmotic pressure, pH balance, and nerve signal transmission in biological systems (e.g., Na? and K? ions).
Himalayan pink salt gets its color from trace amounts of iron oxide and other minerals.
Acidic salts contain replaceable hydrogen ions and form acidic solutions (e.g., NaHSO?). Basic salts contain hydroxide ions and form basic solutions (e.g., Al(OH)?Cl).
Mixed salts contain more than one cation or anion in the same compound. An example is bleaching powder (Ca(OCl)?·CaCl?·2H?O).
Salts are used in industries for making soaps (sodium salts of fatty acids), fertilizers (e.g., ammonium nitrate), and glass manufacturing (e.g., sodium carbonate).
Solubility depends on the salt’s chemical nature. Some salts, like NaCl, are highly soluble, while others, like BaSO?, are insoluble in water.
Hydrated salts are salts that contain water molecules within their crystal structure. For example, CuSO?·5H?O is copper sulfate pentahydrate.
Calcium carbonate is a salt because it is formed by the reaction of calcium hydroxide (a base) with carbonic acid, resulting in the neutral compound CaCO?.
The "salty" taste is associated with the sodium ion (Na?). Salts with low sodium content or different cations may not taste salty.
Table salt is refined sodium chloride (NaCl) often mixed with anti-caking agents and iodine. Rock salt is unrefined and may contain other minerals, giving it a different texture and taste.
The color of a salt is often determined by the transition metal ion present in it. For example, copper salts (e.g., CuSO?) are blue, while iron salts can be yellow or green.
Not all salts conduct electricity. Solid salts do not conduct electricity, but when dissolved in water or molten, salts dissociate into ions and become good conductors.
Salts are named based on the cation (metal or positive ion) first, followed by the anion (non-metal or negative ion). For example, in NaCl, sodium (Na?) is the cation, and chloride (Cl?) is the anion.
A complex salt contains a central metal ion bonded to multiple ligands in a coordinated arrangement, forming a complex ion (e.g., K?[Fe(CN)?]).
Normal salts are formed from the complete neutralization of an acid by a base and consist of a single type of ion pair (e.g., NaCl). Double salts are combinations of two simple salts that exist as a single crystalline structure (e.g., potash alum).
Black salt is a type of rock salt rich in sulfur compounds, often used in Indian cuisine and ayurvedic treatments for its distinct taste and digestive properties.
A double salt is a compound made up of two different salts crystallized together. Examples include potash alum (KAl(SO?)?·12H?O).
Most Common Salt: Sodium chloride (NaCl), widely used in daily life. Rare Salts: Cesium chloride (CsCl), used in specialized applications.
Refined Sodium Chloride (NaCl): Common table salt is one of the purest forms. Himalayan Pink Salt: Claimed to have additional minerals but may not be purer than table salt.
Neutral Salts: Have a pH around 7 (e.g., NaCl). Acidic Salts: Have a pH less than 7 (e.g., NH?Cl). Basic Salts: Have a pH greater than 7 (e.g., Na?CO?).
Solubility: Most salts are soluble in water, but some, like barium sulfate (BaSO?), are not. Conductivity: Salts conduct electricity when dissolved in water due to ion formation. Crystalline Structure: Salts generally form well-defined crystals. Melting Point: High melting points are typical for ionic salts. Neutrality: Neutral salts like NaCl are neither acidic nor basic.
Neutral Salts: Formed by the reaction of a strong acid with a strong base (e.g., NaCl). Acidic Salts: Formed when a strong acid reacts with a weak base (e.g., NH?Cl). Basic Salts: Formed when a strong base reacts with a weak acid (e.g., Na?CO?). Complex Salts: Contain a complex ion, often involving transition metals (e.g., K?[Fe(CN)?]). Double Salts: Exist only in solid form and dissociate into simple ions in water (e.g., alum).
Sodium chloride (NaCl) Potassium chloride (KCl) Calcium carbonate (CaCO?) Magnesium sulfate (MgSO?) Copper sulfate (CuSO?) Ammonium nitrate (NH?NO?) Sodium bicarbonate (NaHCO?) Sodium sulfate (Na?SO?) Zinc sulfate (ZnSO?) Aluminum chloride (AlCl?)
Normal Salts: Formed by the complete neutralization of an acid by a base (e.g., NaCl, KNO?). Acidic Salts: Contain replaceable hydrogen ions and are derived from the partial neutralization of a polybasic acid (e.g., NaHSO?, KH?PO?). Basic Salts: Contain hydroxide ions and result from the partial neutralization of a polyacidic base (e.g., BiOCl, Al(OH)?Cl). Double Salts: Formed by the combination of two simple salts and dissociate completely in water (e.g., Mohr's salt - FeSO?(NH?)?SO?·6H?O).
