Starting with sodium chloride how would you proceed to prepare (i) sodium metal (ii) sodium hydroxide (iii) sodium peroxide (iv) sodium carbonate ?

Explanation

a. Sodium metal is manufactured by electrolysis of a fused mixture of `NaCl(40%)` and `CaCl(60%)` in Down's cell at `873 K` using iron cathode and graphite anode.`Na` is liberated at the anode while `Cl_(2)` is evolved at the cathode.
`"At cathode":Na_(("melt"))^(o+)+e^(-)rarrNa_(l)`
`"At anode":2Cl_(ө)("melt")^(o+)rarrCl_2(g)+2e^(-)`
b. Sodium hydroxide is manufactured by electrolysis of aqueous `NaCl("brine")` in Castner-Kellner cell uisng mercury cathode and carbon anode. Sodium metal which is discharged at the cathode combines with mercury to form sodium amalgam. `Cl_(2)` gas is evolved at the anode.
`"At cathode":Na^(o+)+e^(-)rarrunderset("Sodium")(Na)`
`2Na+xHgrarrunderset("Sodium amalgam")(Na_(2)Hg_(x)`
At anode:`2Cl^(ө)rarr Cl_(2)+2e^(-)`
The amalgam thus obtained is treated with water to form sodium hydroxide and hydrogen gas.
`MG_(2)Hg_(x)+2H_(2)Orarr2NaOH+xHg+H_(2)`
c. Sodium peroxide is obtained by heating sodium in excess of air. The initially fromed sodium oxide reacts with more `O_(2)` to form `Na_(2)O_(2)`.
`2Na+O_(2)rarrNa_(2)O`
`2Na_(2)O+O_(2)rarrNa_(2)O_(2)`
d. Sodium carbonate is obtained by Solvay ammonia process as discussed in answer to Question 12.
When `CO_(2)` is passed through a concentrated solution of brine saturated with `NH_(3),NaHCO_(3)` get precipitated. `NaHCO_(3)` on subsequent heating gives `Na_(2)CO_(3)`.
`NaCl+NH_(3)+CO_(2)+H_(2)OrarrNaHCO_(3)darr+NH_(4)Cl`
`2NaHCO_(3)overset(Delta)rarrNa_(2)CO_(3)+CO_(2)+H_(2)O`