Discuss the various reactions that occur in the Solvay process.
Solvay process is used to prepare sodium carbonate.
When carbon dioxide gas is bubbled through a brine solution saturated with ammonia, sodium hydrogen carbonate is formed. This sodium hydrogen carbonate is then converted to sodium carbonate.
Step 1: Brine solution is saturated with ammonia.
`2NH_3 + H_2O + CO_2 -> (NH_4)_2 CO_3`
This ammoniated brine is filtered to remove any impurity.
Step 2: Carbon dioxide is reacted with this ammoniated brine to result in the formation of insoluble sodium hydrogen carbonate.
Step 3: The solution containing crystals of NaHCO3 is filtered to obtain NaHCO3.
Step 4: NaHCO3 is heated strongly to convert it into NaHCO3.
`2NaHOC_3 -> Na_2CO_3 + CO_2 + H_2O`
Step 5: To recover ammonia, the filtrate (after removing NaHCO3) is mixed with Ca(OH)2 and heated.
The overall reaction taking place in Solvay process is `2NaCl + CaCO_3 -> Na_2CO_3 + CaCl_2`