Washing soda is sodium carbonate containing 10 molecules of water of crystallisation. That is, washing soda is sodium carbonate decahydrate.
The formula of washing soda is Na2CO3.H2O. Sodium carbonate which does not contain any water of crystallisation is called anhydrous sodium carbonate, Na2CO3. Anhydrous sodium carbonate ( Na2CO3 ) is commonly known as 'soda ash'. Washing soda is an important chemical obtained from sodium chloride
( or common salt ).
