Sodium sulphate is a white crystalline compound with the formula Na2SO4. It is used in detergents, papermaking, and glassmaking industries as a filler, a drying agent, and a defoamer.
| IUPAC Name | Disodium sulfate |
| Molecular Formula | Na2SO4 |
| CAS Number | 7757-82-6 |
| Synonyms | Disodium sulfate, Sodium sulfate anhydrous, sodium sulphate |
| InChI | InChI=1S/2Na.H2O4S/c;;1-5(2,3)4/h;;(H2,1,2,3,4)/q2*+1;/p-2 |
Na2So4 Molar Mass
Sodium sulfate has a molar mass of 142.04 g/mol. It is an ionic compound that consists of two sodium cations (Na+) and one sulfate anion (SO42-). The molar mass is calculated by adding the atomic masses of all the atoms in one molecule of sodium sulfate. In this case, we have two sodium atoms with a mass of 22.99 g/mol each, one sulfur atom with a mass of 32.06 g/mol, and four oxygen atoms with a mass of 15.99 g/mol each. Adding these up gives us the molar mass of sodium sulfate.
Sodium Sulphate Boiling Point
Sodium sulfate has a high boiling point of 1,429 °C (2,604 °F). This is due to the ionic nature of the compound, which creates strong electrostatic forces of attraction between the positively charged sodium ions and the negatively charged sulfate ions. These forces require a large amount of energy to overcome, which is why the boiling point of sodium sulfate is so high.
Sodium Sulphate Melting Point
The melting point of sodium sulfate varies depending on its water content. Anhydrous sodium sulfate (without water) has a melting point of 884 °C (1,623 °F). However, sodium sulfate decahydrate (with ten molecules of water) melts at a lower temperature of 32.4 °C (90.3 °F). The presence of water molecules in the crystal structure of sodium sulfate decahydrate weakens the ionic bonds between the sodium and sulfate ions, which reduces the melting point.
Sodium Sulphate Density g/ml
The density of sodium sulfate varies depending on its form. Anhydrous sodium sulfate has a density of 2.664 g/cm3, while sodium sulfate decahydrate has a density of 1.464 g/cm3. The difference in density is due to the presence of water molecules in the crystal structure of the decahydrate, which increases its volume and decreases its density.
Sodium Sulphate Molecular Weight
The molecular weight of sodium sulfate is 142.04 g/mol. This is the mass of one molecule of sodium sulfate, which consists of two sodium ions and one sulfate ion.
Sodium Sulphate Structure
Sodium sulfate has a crystalline structure that consists of repeating units of sodium and sulfate ions. The sulfate ion is a tetrahedron with four oxygen atoms at the corners and a sulfur atom at the center. The sodium ion is a small sphere that sits between the sulfate ions. The crystal structure of sodium sulfate can vary depending on its water content. Anhydrous sodium sulfate has a different crystal structure than sodium sulfate decahydrate.
Sodium Sulphate Formula
The chemical formula of sodium sulfate is Na2SO4. This means that each molecule of sodium sulfate contains two sodium ions (Na+) and one sulfate ion (SO42-). The formula represents the simplest whole number ratio of atoms in one molecule of the compound.
| Appearance | White crystalline solid |
| Specific Gravity | 2.664 g/cm3 (anhydrous), 1.464 g/cm3 (decahydrate) |
| Color | White |
| Odor | Odorless |
| Molar Mass | 142.04 g/mol |
| Density | 2.664 g/cm3 (anhydrous), 1.464 g/cm3 (decahydrate) |
| Melting Point | 884 °C (anhydrous), 32.4 °C (decahydrate) |
| Boiling Point | 1,429 °C |
| Flash Point | Not applicable |
| Water Solubility | 44.1 g/100 mL (anhydrous), 47.6 g/100 mL (decahydrate) |
| Solubility | Soluble in water, insoluble in ethanol |
| Vapour Pressure | 0.01 mmHg at 20 °C |
| Vapour Density | Not applicable |
| pKa | 1st: 2.01, 2nd: 7.20, 3rd: 9.41 |
| pH | 9-11 (10% solution) |
Sodium Sulphate Safety and Hazards
Sodium sulfate is generally considered safe for use, but can cause irritation or harm in some circumstances. It can irritate the skin, eyes, and respiratory system upon contact or inhalation. Ingesting large amounts can cause nausea, vomiting, and diarrhea. It can also be harmful to aquatic life if released into waterways. Sodium sulfate is not considered a flammable or explosive material. However, when heated or exposed to high temperatures, it can release toxic fumes. It is important to follow proper handling procedures, wear protective equipment, and store sodium sulfate in a safe and secure location.
| Hazard Symbols | None |
| Safety Description | S24/25: Avoid contact with skin and eyes. S36/37: Wear suitable protective clothing and gloves. |
| UN IDs | UN 2118 |
| HS Code | 2833.11.00 |
| Hazard Class | Non-hazardous |
| Packing Group | Not applicable |
| Toxicity | LD50 (oral, rat): 5,900 mg/kg |
Sodium Sulphate Synthesis Methods
There are various methods to synthesize sodium sulfate, including the reaction of sodium chloride with sulfuric acid or the reaction of sodium hydroxide with sulfuric acid.
To produce sodium sulfate, the reaction of sodium chloride and sulfuric acid generates sodium sulfate and hydrogen chloride gas. The process minimizes harmful fumes by conducting the exothermic reaction under controlled conditions. Subsequently, the solution undergoes filtration before evaporation to produce sodium sulfate crystals.
The synthesis of sodium sulfate also entails combining sulfuric acid and sodium hydroxide to form sodium sulfate and water. The reaction is exothermic and requires careful handling to avoid boiling over. After filtering the mixture, the resulting solution is subjected to evaporation to yield sodium sulfate crystals.
Another method involves the reaction of sodium carbonate with sulfuric acid, producing sodium sulfate, water, and carbon dioxide gas. This method requires the use of a fume hood due to the release of toxic fumes. The solution is then filtered and evaporated to obtain sodium sulfate crystals.
Other industrial processes, such as the production of rayon, detergents, and glass, also produce sodium sulfate as a byproduct. These processes produce sodium sulfate as a waste material, which can be purified and reused for other purposes.
Sodium Sulphate Uses
Sodium sulfate has a wide range of uses in various industries, including:
- Detergents: Used as a filler in powdered detergents, helping to increase the volume and improve the flow of the product.
- Glass: Used as a flux in the manufacture of glass, helping to reduce the melting point and improve the clarity of the final product.
- Textiles: Used in the production of synthetic fibers, such as rayon, to improve the strength and durability of the material.
- Paper: Used as a pulping agent in the production of paper, helping to break down the wood fibers and remove impurities.
- Food: Used as a food additive, primarily as a thickener and emulsifier in processed foods.
- Pharmaceuticals: Used in the production of certain medications, such as laxatives, to help treat constipation.
- Chemicals: Used in the production of various chemicals, including sodium sulfide, sodium silicate, and sodium bicarbonate.
- Water treatment: Used in water treatment plants to remove calcium and magnesium ions from hard water.
- Oil drilling: Used in oil drilling as a weighting agent, helping to control the density of the drilling fluid.
Questions:
Q: What is the formula of sodium sulphate?
A: The chemical formula for sodium sulfate is Na2SO4.
Q: What is sodium sulphate?
A: Sodium sulfate is a white crystalline solid that is commonly used in various industrial applications, including detergents, glass, textiles, paper, and food.
Q: Is sodium sulphate acidic or basic?
A: Sodium sulfate is neither acidic nor basic; it is a neutral compound.
Q: What is the colour of sodium sulphate? A: Sodium sulfate is a white crystalline solid, and therefore, it is colorless.