Q21 of 30 Page 1

List the important products of the Chlor-alkali process. Write one important use of each.

OR


How is washing soda prepared from sodium carbonate? Give its chemical equation, State the type of this salt, Name the type of hardness of water which tan be removed by it?


Important products of Chlor-alkali process are

(i) Sodium Hydroxide


Use: It is used for making soaps and detergents.


(ii) Chlorine


Use: It is used in the production of bleaching powder.


(iii) Hydrogen


Use: It is used in the production of Hydrochloric Acid,


OR


Washing soda is obtained by rehydration of anhydrous sodium carbonate.


Na2CO3 + 10H2O → Na2CO3.10H2O


It is the basic salt.


Na2CO3 can remove temporary and permanent hardness from water. Sodium carbonate is soluble but calcium carbonate and magnesium carbonate are insoluble.


The carbonate ions from sodium carbonate react with the calcium and magnesium ions in the water to produce insoluble precipitates. For example:


calcium ions + sodium carbonate → calcium carbonate + sodium ions


Ca2+(aq) + Na2CO3(aq) → CaCO3(s) + 2Na+(aq)



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