How to prepare NaCl from the Brine salt solution (Sea water) ?

1.	How to prepare NaCl from the Brine salt solution (Sea water) ?
Answer» Solution : The most abundant source of sodium chloride is sea water which contains 2.7 to 2.9% by mass of the salt. Common salt is generally obtained by evaporation of sea water. Crude sodium chloride, generally obtained by crystallization of brine solution, contains sodium sulphate, calcium sulphate, calcium chloride and magnesium chloride as impurities. Calcium chloride, `CaCl_(2)`, and magnesium chloride, `MgCl_(2)` are impurities because they are deliquescent (ABSORB moisture easily from the atmosphere). To obtain pure sodium chloride, the crude salt is dissolved in minimum amount of water and filtered to remove insoluble impurities. The solution is then saturated with hydrogen chloride GAS. Crystals of pure sodium chloride separate out. Calcium and magnesium chloride, being more soluble than sodium chloride, remain in solution. Properties: Sodium chloride melts at 1081K. It has a solubility of 36.0g in 100g of water at 273K. The solubility does not increase appreciably with increase in TEMPERATURE. Uses : (i) It is used as a common salt or table salt for domestic purpose. (ii) It is used for the preparation of `Na_(2)O_(2)` NaOH and `Na_(2)CO_(3)`.

Discussion