Write the equations during the preparation of sodium carbonate by solvay process.

Explanation

Solvay process to prepare `Na_(2)CO_(3)` is as follows.
Step 1 : Ammonical brine is prepared : Ammonia is passed through saturated solution of sodium chloride in water and cooled to `30^(@)C`.
Step 2 : Carbonation : Carbondioxide is passed through ammonical brine solution to give ammonium hydrogencarbonate later to give a mikly solution of sodium hydrogen carbonate.
`NH_(3) + H_(2) O to NH_(4) OH` (ammonium hydroxide)
`NH_(4) OH + CO_(2) to N_(2) HCO_(3)` (ammonium hydrogen carbonate)
`NH_(4) HCO_(3) + NaCI to underset(("Sodium bicarbonate"))(NaHCO_(3)) + NH_(4) CI`
Sodium bicarbonate is removed away by filration to get solid sodiun bicarbonate.
Step 3 : Calcination : solid `NaHCO_(3)` on heating gives sodium carbonate and `CO_(2)`
`NAHCO_(3) overset(Delta)(to) Na_(2) CO_(3) + H_(2) O + CO_(2) uArr`
Again after recrystallisation iron water produces sodium carbonate.
`Na_(2) CO_(3) (aq) + 10 H_(2) O overset("recrystallination")(to) Na_(2)CO_(3). 10H_(2)O`
Recovery of ammonia: Quick lime is heatd with `NH_(4)CI` in above step to give ammonia gas which is used again to prepare ammonical brine.
`CaO + 2NH_(4) CI overset(Delta)(to) CaCI_(2) + 2NH_(3) uArr + H_(2) O`