Characteristic

 

Sodium sulfate (also known as sodium sulphate or sulfate of soda) is the inorganic compound with formula Na₂SO₄ as well as several related hydrates. All forms are white solids that are highly soluble in water.

Chemical formula:Na₂SO₄

Molar mass: 142.04 g/mol (anhydrous);322.20 g/mol (decahydrate)

Appearance: white crystalline solid hygroscopic

Odor: odorless

Density:2.664 g/cm³ (anhydrous);1.464 g/cm³ (decahydrate)

Melting point:884 °C (1,623 °F; 1,157 K) (anhydrous);32.38 °C (decahydrate)

Boiling point:1,429 °C (2,604 °F; 1,702 K) (anhydrous)

Solubility in water:anhydrous:4.76 g/100 mL (0 °C);13.9 g/100 mL (20 °C);42.7 g/100 mL (100 °C);heptahydrate:19.5 g/100 mL (0 °C);44 g/100 mL (20 °C)

Solubility: insoluble in ethanol;soluble in glycerol, water and hydrogen iodide

Magnetic susceptibility (χ):−52.0·10⁻⁶ cm³/mol

Refractive index (nD):1.468 (anhydrous);1.394 (decahydrate)

Crystal structure:orthorhombic (anhydrous);monoclinic (decahydrate)

 

Application

 

Sodium sulfate decahydrate is used as a laboratory reagent to precipitate protein. It is largely used as filler in powdered home laundry detergents. It facilitates in leveling, reducing negative charges on fibers, thereby allows dye to penetrate evenly. It avoids the corrosion of stainless steel vessels used in dyeing. It is also used as a laxative and effectively replaces the drug paracetamol in the body.