Our Objective 

To identify washing soda or baking soda from the given set of samples and understand the chemistry behind the reaction. 

The Theory

Washing soda (Na2CO3 .10H2O) and baking soda (NaHCO3) are white solids. Their aqueous solutions are Alkaline and turn red litmus blue. Carbonates and Hydrogencarbonates react with dilute acids and produce Carbon dioxide gas which turns lime water milky.  

CO (aq)+H O (l) H CO (aq)+2OH (aq) 

HCO3 – (aq) + H2O (l) → H2CO3 (aq) + OH– (aq) 

Na2CO3 (s) + 2HCl (aq) → 2NaCl (aq) + H2O (l) + CO2 (g) 

NaHCO3 (s) + HCl (aq) → NaCl (aq) + H2O (l) + CO2 (g) 

Ca (OH)2 (aq) + CO2 (g) → CaCO3 (s) + H2O (l) 

Lime water                               Milky 

On passing excess of CO2 through limewater, Calcium Hydrogencarbonate is formed. It is soluble in water and forms a colourless solution. 

CaCO3 (s) + H2O (l) + CO2 (g) → Ca (HCO3) 2 (aq). 

In this experiment, we shall make use of litmus paper and lime water test to identify the washing soda or baking soda from the given samples of chemicals.

What is Washing Soda? 

Washing soda is a white crystalline solid and its chemical formula is Na2CO3.10H2O. It is an inorganic hydrate of Sodium carbonate. It was extracted from the ashes of plants growing in Sodium-rich soils and hence the name soda ash. It is highly soluble in water and forms a strongly Alkaline water solution. 

Uses of Washing Soda 

• Used as a cleansing agent in industries and households. 
• It is prominently used in glass, paper, textile, soap, and detergent industries  
• It is used in the process of softening water. 

What is Baking Soda? 

Sodium bicarbonate, also known as baking soda or bicarbonate of soda, is a chemical compound with the formula NaHCO3 and the IUPAC designation Sodium Hydrogencarbonate. A Sodium cation (Na+) and a bicarbonate anion (HCO3) combine to form this salt. Sodium bicarbonate is a white, crystalline substance that is commonly found as a fine powder. It tastes slightly salty and Alkaline, like washing soda (Sodium carbonate). 

Uses of Baking Soda 

• Reduces the acidity in the stomach. 
• Due to the formation of soapy foam, it is used in fire extinguishers. 
• It is used in ear drops, cosmetics and personal care products. 
• It is used as an ingredient in the manufacturing of antacids. 

Preparation of Washing soda or Baking soda 

Washing soda is synthesized through Solvay’s process. Solvay’s process involves the reaction of Sodium Chloride, Ammonia, and Carbon dioxide in water. Carbon dioxide involved is produced through Calcium Carbonate and the Calcium oxide left is used in recovering Ammonia from Ammonium Chloride. 

At first, Sodium bicarbonate is obtained which is then converted to Sodium Carbonate on heating. Finally, washing soda is produced by recrystallization of Sodium Carbonate. 

Learning Outcomes 

• Students will be able to understand the terms ‘Washing soda' and 'Baking soda’ through this experiment.
• Students will be able to understand the preparation and uses of washing soda and baking soda.
• Students are able to perform the experiment better in real lab after experiencing it in the virtual lab.