What is Sodium Chloride, NaCl?
Sodium Chloride is commonly known as salt, which is an ionic compound having the chemical formula (NaCl), representing a 1:1 ratio of chloride and sodium ions. Sodium chloride is a salt that is the most responsible for the salinity of seawater and of the extracellular fluid of various multicellular organisms. It is commonly used as a condiment and food preservative in its edible form of table salt.
Certain huge amounts of NaCl are used in numerous industrial processes and are a major source of sodium and chlorine compounds that are used as feedstocks for further chemical syntheses. A second major sodium chloride application is the de-icing of roadways in sub-freezing weather.
About 1% to 5% of the seawater is made of sodium chloride. It is a solid crystalline material white in colour. It is called a saline solution in aqueous form.
The molecular weight of NaCl is 58.44g/mol.
This is a water-soluble compound with a sodium cation and chloride anion. It is widely well-known as table salt and is used mostly in the food industry for preservation and flavouring purposes. The pH value of NaCl is 7.
Structure of NaCl
The structure of NaCl can be given as,
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Properties of Sodium Chloride
Physical Properties of NaCl
Sodium chloride, a white crystalline solid, contains a density of 2.165 g/mL, a melting point of 801 °C, and a boiling point is about 1,413 °C. It is also available as aqueous solutions with different concentrations, which are known as saline solutions.
Chemical Properties of NaCl
Sodium chloride is a readily soluble compound in water and other polar solvents and is a stable solid. It decomposes only at high temperatures to produce toxic fumes of disodium oxide (Na2O) and hydrochloric acid (HCl).
Uses of Sodium Chloride
Of the many uses of NaCl, a few of them are listed below.
Sodium chloride is well known as table salt and is widely used in the food industry for flavouring and preservation.
Also, it is used to produce various essential chemicals, including sodium hydroxide, baking soda, sodium carbonate, hydrochloric acid, and more.
It also has applications in the textile industries, oil refineries, paper and pulp industry, fire-retardants, road constructions, and the rubber industries.
In the soda ash industry, it is used to produce sodium carbonate through the Solvay process.
Another important use of sodium chloride is the de-icing of roads and sidewalks in snowy and cold regions. These saline solutions are used for various medical purposes as well.
The compound is also used in cleaners like shampoo, toothpaste, and even in water softeners.
Usage of Sodium Chloride for a Human Body
Nutrient Transportation and Absorption
Both sodium and chloride play an essential role in our small intestine. Sodium helps your body absorb sugar, water, chloride, and amino acids (which are the building blocks of protein).
When chloride is in the form of hydrochloric acid (hydrogen and chloride), it acts as a gastric juice component. It helps our body to digest and absorb nutrients.
Maintaining Resting Energy
Sodium and potassium are the electrolytes in the fluid inside and outside of our body cells. The balance between these two particles contributes to how the cells maintain the energy of the body.
Also, it is how the nerves send signals to the brain, how the muscles contract, and how the heart functions.
Maintaining Hydration and Blood Pressure
The brain, kidneys, and adrenal glands work together to regulate the amount of sodium in the human body. Chemical signals stimulate the kidney to hold on to water so that it can get rid of excess water through the urine or be reabsorbed into the bloodstream.
When there’s too much sodium in our bloodstream, the brain signals the kidneys to release more water into your blood circulation. This leads to an increase in blood volume and blood pressure. Decreasing your sodium intake can lead to less water being absorbed into the bloodstream. The result is lower blood pressure.
Occurrence of Sodium Chloride
Usually, most of the chemical compounds consisting of chlorine or sodium are derived from salts. It is distributed abundantly in nature. Salt is a significant ingredient in seawater dissolved materials.
Pure salt can be obtained from halite minerals. Sodium chloride is created by mining the deposits, and the brine solution is collected by transferring water into the deposits. Therefore, the salts are dissolved, and the solution is pumped out.
Seawater evaporation is one of the main methods to extract salt and is most commonly practised in countries like India. Usually, the crystals obtained consist of impurities like sodium sulfate, calcium sulfate, and so on. Pure crystals are produced by dissolving salts with little water and filtering the solution.
Preparation of Sodium Chloride
However, sodium and chlorine respond together to generate a familiar substance to nearly everybody across the globe: sodium chloride, common salt, or table salt.
2Na(s) + Cl2(g) → 2NaCl(s)
FAQs on Sodium Chloride
1. What are the key physical and chemical properties of sodium chloride as outlined in the CBSE syllabus?
Sodium chloride is a white crystalline solid with a density of 2.165 g/cm³, a melting point of 801°C, and a boiling point of 1,413°C. It dissolves readily in water to form a neutral solution (pH 7). Chemically, it is a stable ionic compound that decomposes only at high temperatures, yielding sodium oxide and hydrochloric acid.
2. Describe the structure and formation process of sodium chloride in accordance with the NCERT guidelines.
Sodium chloride (NaCl) consists of a repeating three-dimensional lattice, where each sodium ion is surrounded by six chloride ions and vice versa. It forms through the direct reaction of sodium metal and chlorine gas: 2Na(s) + Cl2(g) → 2NaCl(s). This crystalline arrangement provides stability and accounts for its distinct physical properties.
3. Explain the occurrence and extraction methods of sodium chloride commonly discussed in board exams.
Sodium chloride is found abundantly in seawater (about 1–5%) and as rock salt (halite) deposits. It is extracted by either mining rock salt or evaporating seawater, with the latter often used in countries like India. Impurities are removed by dissolving the salt in water and filtering, yielding pure sodium chloride crystals.
4. How is sodium chloride essential for human physiological functions, and what happens if its balance is disrupted?
Sodium and chloride ions help regulate fluid balance, nerve transmission, and muscle contraction. Sodium aids in nutrient absorption, while chloride (as part of hydrochloric acid) assists digestion. Too little sodium may cause low blood pressure and muscle cramps, while excess can raise blood pressure due to fluid retention.
5. Discuss the main industrial and household applications of sodium chloride relevant to the CBSE Chemistry syllabus.
Sodium chloride is widely used as
- Table salt for seasoning and preservation
- A raw material in the manufacture of chemicals (e.g., sodium hydroxide, hydrochloric acid, sodium carbonate)
- De-icing agent for roads
- Water softening
- In medical saline solutions
- In textile, oil refining, rubber, and paper industries
6. What is the difference in the behaviour of sodium chloride in its solid, molten, and aqueous states?
In its solid state, sodium chloride forms a rigid lattice with ions fixed in position. In the molten state, ions are free to move, allowing conduction of electricity. In aqueous solution, Na+ and Cl- ions disperse throughout water, interact with dipoles, and can participate in further reactions.
7. Why is sodium chloride considered a neutral salt, and how does this relate to its pH in solution?
Sodium chloride is a neutral salt because it results from the reaction of a strong acid (hydrochloric acid) and a strong base (sodium hydroxide), producing a solution with a pH of 7 when dissolved in water. This lacks any acidic or basic character in standard conditions.
8. How does the excessive use of sodium chloride impact human health and the environment?
Overconsumption of sodium chloride can lead to high blood pressure and increase the risk of heart disease in humans. Environmentally, large-scale use for de-icing can lead to soil and water salinization, affecting plant growth and aquatic life.
9. What are common misconceptions students have about sodium chloride’s chemical nature, and how can they be clarified?
A typical misconception is that sodium chloride possesses distinct acidic or basic properties, while in reality, it is neutral. Another is believing sodium and chlorine exist as atoms within salt; in truth, they form stable ions (Na+ and Cl-) in the crystal lattice.
10. How does the CBSE board typically assess students’ understanding of sodium chloride in exams?
The CBSE board evaluates knowledge of sodium chloride through questions on its properties, uses, extraction, ionic structure, and role in daily life. Students may be asked to
- Write balanced chemical equations for its formation
- Explain physical and chemical properties
- Discuss biological and industrial importance
