Question

Consider the following substances:
NaCl, Ca(OH)₂, NaHCO₃, NH₃, Na₂CO₃, H₂O, Cl₂, CO₂, CaSO₄.2H₂O, 2CaSO₄.H₂O, CaOCl₂
 Which four substances are utilised in the production of washing soda?

Answer 1

NaCl, NH₃, H₂O, CO₂ are utilised in the production of washing soda.
The chemical reaction involved can be shown in three steps:
i) Production of sodium hydrogen carbonate:
NaCl + NH₃ + H₂O + CO₂ → NaHCO₃ +NH₄Cl
ii) Production of anhydrous sodium carbonate upon heating sodium hydrogen carbonate:
2NaHCO₃ → Na₂CO₃ + CO₂ + H₂O
iii) Production of hydrated sodium carbonate when anhydrous sodium carbonate is dissolved in water:
Na₂CO₃ + 10H₂O → Na₂CO₃.10H₂O