A chemical compound ‘X’ is used in the soap and glass industry. It is prepared from brine. (a) Write the chemical name, common name and chemical formula of ‘X’. (b) Write the equation involved in its preparation. (c) What happens when it is treated with water containing Ca or Mg salts?

(a) The chemical name is Sodium carbonate. Its common name is Washing Soda. The chemical formula of the compound in its hydrated form is Na₂CO₃.10H₂O.

(b) The equation involved in its preparation are:

$NaCl + H_2O + CO_2 + NH_3 → NH_4Cl + NaHCO_3$

$2NaHCO_3  → Na_2CO_3 + H_2O + CO_2$

$Na_2CO_3 + 10H_2O → Na_2CO_3 . 10H_2O$

(c) Washing Soda helps in removing permanent hardness from water. It forms insoluble Ca or Mg salts in the form of scum when it is treated with water containing Ca or Mg salts.