Washing Soda (Sodium Carbonate)

Washing soda is used in a variety of applications, ranging from home to industrial. It’s an alkaline substance with a high alkaline character that can eliminate stubborn stains from textiles while they’re being washed. The formula for washing soda is Na₂CO₃.10H₂O. Sodium carbonate is the chemical term for washing soda. Soda ash is a hydrated salt of sodium carbonate in chemical terms.

Sodium Carbonate Formula

Sodium Carbonate is also known as Washing Soda. The chemical formula of Sodium Carbonate or Washing Soda is Na₂CO₃.10H₂O, where 10H₂O is the water of crystalization.

Preparation of Sodium Carbonate

Solvay method is required for the synthesis of sodium carbonate, and the steps involved in sodium carbonate manufacturing are described below:

Step 1: Purification of Brine

A solution of salt and water, called brine is purified in the first step. This process is important to remove the impurities and therefore increase the yield of the final product. Evaporation produces concentrated brine, while precipitation removes impurities such as calcium, magnesium, and other minerals coming from the rock salts. The concentrated brine solution is filtered before being mixed with ammonia in the ammonia tower.

Step 2: Formation of Sodium Hydrogen Carbonate

In the second step, purified brine is transferred into another chamber, and ammonia passes through it. This ammonia reacts with salt water to give ammoniated brine and heat. In the next step, this ammoniated brine reacts with Carbon dioxide (produced via decomposing CaCO₃ at 900°C) to give sodium bicarbonate and ammonium chloride. These conditions are controlled in such a way as to maximise the precipitation of sodium bicarbonate, which is extracted using a rotary pump.

NH₃ + CO₂ + NaCl + H₂O → NaHCO₃ + NH₄Cl

Step 3: Formation of Sodium Carbonate

In this step sodium carbonate (Na₂CO₃) is produced by the thermal decomposition of sodium bicarbonate (NaHCO₃) at 300°C. As a result, sodium carbonate crystals form.

2NaHCO₃ → Na₂CO₃ + CO₂ + H₂O

Step 4: Recovery of Ammonia

This process involves the recovery of ammonia from the previous steps. In this step, a distillation column is used to recover ammonia. First NH₄Cl solution is treated with lime water (Ca(OH)₂) to obtain the ammonia as the final product. The Solvay process uses this ammonia again, and CaCl₂ is obtained as a by-product.

2NH₄Cl + Ca(OH)₂ → 2NH₃ + CaCl₂ + H₂O

Properties of Sodium Carbonate

Various Properties of Sodium Carbonate are,

• It’s a crystalline solid that’s white in colour.
• It comes in monohydrated (Na₂CO₃.10H₂O), anhydrous (Na₂CO₃), heptahydrate (Na₂CO₃.7H₂O), and decahydrate (Na₂CO₃.10H₂O) forms.
• In nature, sodium carbonate is a basic substance.
• It has a melting point of 851°C.
• It loses its water in the presence of heat and forms an anhydrous salt (soda ash).

Na₂CO₃.10H₂O → Na₂CO₃.H₂O → Na₂CO₃ (at 373 K)

Uses of Sodium Carbonate

Various uses of Sodium Carbonate are discussed below in this article,

• In industry and the home, it is used as a cleaning agent.
• It’s used in the paper, textile, soap, and detergent sectors, among others.
• It is utilised in the water-softening process.
• It’s a material used in the production of glass.
• In laundries, it is one of the most significant agents.

Plaster of Paris, Baking Soda and Washing Soda are a few compounds which are widely used in our daily life. Sodium bicarbonate commonly known as baking soda is a chemical compound with the formula NaHCO₃. Sodium carbonate commonly known as washing soda is a chemical compound with the formula Na₂CO₃. Calcium Sulphate Hemihydrate commonly known as Plaster of Paris is a chemical compound with the formula CaSO₄.1/2H₂O.

In this article, we will learn about Plaster of Paris, Baking Soda and Washing Soda, its preparation, properties, and uses in detail.