Give the preparation,properties,and uses of sodium chloride ($NaCl$ $-$ Rock salt).

(N/A) Preparation: 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 the evaporation of sea water.
Crude sodium chloride,obtained by the crystallization of brine solution,contains impurities like sodium sulphate,calcium sulphate,calcium chloride,and magnesium chloride. 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 a 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,while calcium and magnesium chlorides,being more soluble than sodium chloride,remain in the solution.
Properties: Sodium chloride melts at $1081 \ K$. It has a solubility of $36.0 \ g$ in $100 \ g$ of water at $273 \ K$. The solubility does not increase appreciably with an increase in temperature.
Uses: $(i)$ It is used as a common salt or table salt for domestic purposes. $(ii)$ It is used for the preparation of $Na_{2}O_{2}$,$NaOH$,and $Na_{2}CO_{3}$.