Some Important Chemical Compounds


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       The chemical name of washing soda is sodium carbonate decahydrate, and its chemical formula is Na2CO3.10H2O. So washing soda is hydrated salt of sodium carbonate containing 10 molecules of water of crystallization. But the anhydrous sodium carbonate which doesn’t have any molecule of water of crystallization is commonly known as ‘soda ash’.

       Sodium carbonate occurs in crude forms in East Africa, Egypt, USA etc. In India it occurs in Dehradun, Mathura, Jaunpur, Varanasi, etc. About 1.54 million tons of soda ash (anhydrous sodium carbonate) is produced in India every year.

hydrated salt of copper sulphate

Properties of Washing Soda

  1. Washing soda is a transparent crystalline solid.

  2. Washing soda is soluble in water

  3. The aqueous solution of Washing soda is alkaline in nature i.e. it converts red litmus paper into blue.

  4. Washing Properties:- Washing soda is used as a detergent for washing the clothes because it can attack on the dirt and grease particles present in dirty clothes to remove them.

  5. Reaction with Water:- Washing soda decomposes into ions when dissolved in water to produce alkaline solution.

            Na2CO3           2Na+      +      CO32–

             2H2O           2H+      +      2OH

    2Na+ + CO32– + 2H+ + 2OH        2NaOH + H2CO3

    The ionic solution of washing soda is alkaline in nature due to the presence of OH- ions in it.

  6. Action of Air:- Washing soda crystals are when exposed to air then 9 molecules of water of crystallization evaporates leaving behind sodium carbonate monohydrate which is in the form of white powder.

    Na2CO3.10H2O          NaCO3.H2O    +    9H2O
    Washing soda                              Sodium carbonate      Water

    Efflorescence or Dehydration

           The loss of water of crystallization from the hydrated salt of washing soda to the environment, on keeping it exposed to air, is called efflorescence.

  7. Action of Heat:- When the crystals of washing soda are heated strongly then all the water of crystallization evaporates leaving behind anhydrous sodium carbonate.

    Na2CO3.10H2O          NaCO3      +      10H2O
    Washing soda                           Sodium carbonate       Water

Uses of Washing Soda

  1. Washing soda is used extensively for washing clothes in laundry.

  2. Washing soda is used for softening hard water.

  3. Washing soda is used in the manufacture of many useful compounds such as caustic soda, borax, glass and soap.

  4. Washing soda is also used as a laboratory reagent.