Discuss the preparation and properties of sodium carbonate.

Explanation

Preparation:
Sodium carbonate is prepared by solvay process.
In this process sodium chloride reacts with ammonium bicarbonate and gets precipitated the low soluble sodium bicarbonate.
The lather is prepared by passing `CO_2` into a concentrated solution of NaCl saturated with ammonia. Here `(NH_4)_2 CO_3` followed by `NH_4 HCO_3` are formed.
Chemical equations involved:
`2NH_3+H_2O+CO_2 to (NH_4)_2 CO_3`
`(NH_4)_2 CO_3+H_2O+CO_2 to 2NH_4 HCO_3`
`NH_4HCO_3+ NaCl to NH_4Cl+NaHCO_3`
THe separated `NaHCO_3` Crystals heated to get `Na_2CO_3`
`2NaHCO_3 to Na_2CO_3+H_2O+CO_2`
In this process ammonia is regenerated by `Ca(OH)_2`
`2NH_4Cl+Ca(OH)_2 to 2NH_3+CaCl_2+H_2O`
Properties of washing soda:
`Na_2CO_3` is a white crystalline solid
`Na_2CO_3` exists as a decahydrate `Na_2CO_3.10 H_2O` which is called washing soda.
`Na_2CO_3` is readily soluble in water.
`Na_2CO_3` (decahydrate) when heated it loses the water molecules and forms monohydrate. This monohydrate on heating above 373K it forms monohydrate. This monohydrate on heating above 373K it forms anhydrous form which is called soda ash, a white powder ,
Reactions:
`Na_2CO_3. 10H_2O overset(373K) to underset("Monohydrate")(Na_2CO_3.H_2O +9H_2O)`
`underset("monohydrate")(Na_(2)CO_(3).H_(2)O)overset(gt373K)tounderset("Soda ash")(Na_(2)CO_(3))+H_(2)O`
`Na_2CO_3 (aq)` solution is alkaline (basic in nature) Because it under goes anionic hydrolysis `(PH gt7)`
`CO_3^(-2) +H_2O to HCO_3^(-) +Oh^-`
Uses:
`Na_2CO_3` is used in the manufacturing of glass.
`Na_2CO_3` is used in the manufacturing of borax, caustic soda.
`Na_2CO_3` is used in paper, paints and textile industries.
`Na_2CO_3` is used in softening of water.
`Na_2CO_3` is used in laundries.
`Na_2CO_3` is used an important laboratory reagent both in qualitative and quantitative analysis.