(a) Name the raw materials used in the manufacture of sodium carbonate by Solvay process.
(b) How is sodium hydrogen carbonate formed during Solvay process separated from a mixture of `NH_(4)Cland NaHCO_(3)` ?
(c ) How is sodium carbonate obtained from sodium hydrogen carbonate ?

Explanation

(a) The raw materials used are : NaCl, lime stone or `CaCO_(3) and NH_(3).`
(b) Sodium hydrogen carbonate `(NaHCO_(3))` is sparingly soluble or less soluble in water and gets separted as a preciptate while `NH_(4)Cl` remains in solution. The precipitate is removed by filtation.
(c ) Sodium hydrogen carbonate is converted to sodium carbonate upon heating.
`2NaHCO_(3) overset("heat")to Na_(2)CO_(3)+H_(2)O+CO_(2)`