How is washing soda produced using sodium chloride as one of the raw materials?
Answers
Answer :-
Washing soda is prepared by using the sodium chloride as raw material as following methods .
Step 1:-
the sodium chloride is dissolved in water to prepare the concentrated brine solution.
Step2:-
The carbon dioxide and Ammonia gas is dissolved in concentrated solution of brine to form Ammonium Chloride and sodium bicarbonate.
NaCl + H2O + CO2 + NH3 => NH4Cl + NaHCO3
Step3:-
The sodium bicarbonate is soluble at room temperature and it is easily separated from the solution.
Step4:-
The anhydrous Sodium Bicarbonate is heated and it get decomposed into washing soda carbon dioxide and water.
2NaHCO3 + ∆ => Na2CO3 + CO2 + H2O
Step5:-
The any hydrous sodium bicarbonate is attached with certain water molecules to form the hydrous washing soda.
Na2CO3 + 10.H2O => Na2CO3.10H2O
Answer:
Explanation:
(a) Production of washing soda: Washing soda is produced from sodium chloride (or common salt) in the following three steps:
(i) A cold and concentrated solution of sodium chloride (called brine) is reacted with ammonia and carbon dioxide to obtain sodium hydrogen carbonate :
Sodium chloride (common salt)
NaCl
+
Ammonia
NH
3
+
Water
H
2
O
+
Carbon dioxide
CO
2
→
Sodium hydrogencarbonate
NaHCO
3
+
Ammonium chloride
NH
4
Cl
Sodium hydrogen carbonate formed is only slightly soluble in water, so it precipitates out as a solid.
(ii) Sodium hydrogen carbonate is separated by filtration, dried and heated. On heating, sodium hydrogen carbonate decomposes to form sodium carbonate:
Sodium hydrogencarbonate
2NaHCO
3
Heat
Sodium crbonate (soda ash)
Na
2
CO
3
+
carbon dioxide
CO
2
+
water
H
2
O
The anhydrous sodium carbonate obtained here is called soda ash.
(iii) Anhydrous sodium carbonate (soda ash) is dissolved in water and recrystallised to get washing soda crystals containing 10 molecules of water of crystallisation :
Anhydrous sodium carbonate (Soda ash)
Na
2
CO
3
+
water
10H
2
O
⟶
Sodium carbonate decahydrate (washing soda)
Na
2
CO
3
.10H
2
O