Starting with sodium chloride how would you proceed to prepare

(i) Sodium can be extracted from sodium chloride by Downs process. This process involves the electrolysis of fused NaCl (40%) and CaCl2 (60 %) at a temperature of 1123 K in Downs cell.
Steel is the cathode and a block of graphite acts as the anode. Metallic Na and Ca are formed at cathode. Molten sodium is taken out of the cell and collected over kerosene.
(ii) Sodium hydroxide can be prepared by the electrolysis of sodium chloride. This is called Castner–Kellner process. In this process, the brine solution is electrolysed using a carbon anode and a mercury cathode. The sodium metal, which is discharged at cathode, combines with mercury to form an amalgam
(iii) Sodium peroxide First, NaCl is electrolysed to result in the formation of Na metal (Downs process). This sodium metal is then heated on aluminium trays in air (free of CO2) to form its peroxide
(iv) Sodium carbonate is prepared by Solvay process. Sodium hydrogen carbonate is precipitated in a reaction of sodium chloride and ammonium hydrogen carbonate.

(i) sodium metal:Sodium chloride can be converted into sodium by Downs process. It can be achieved by electrolysis of fused CaCl₂ (60 %) and NaCl (40%) at 1123 K in a special apparatus (Downs cell).

A graphite block is the anode while steel is made the cathode. Metallic Ca and Na are formed at the cathode. Molten Na is supported by dipping in kerosene.

Nacl →Electrolysis Na⁺ + Cl^–

(Molten) At Cathode: 

Na⁺ +e^– → Na At Anode: 

Cl^– - e^– → Cl

(ii)Sodium Hydroxide: By electrolyzing a solution of sodium chloride, we can get Sodium hydroxide. This process is commonly known as Castner- Kellner process. The process is carried out using a mercury cathode and a carbon anode. Sodium metal, deposited at cathode forms an Amalgam by combining with Mercury.

Cathode: Na⁺ +e^– →Hg Na-Amalgam 

Anode; 2 Cl^– → Cl₂ + 2e^– 

Cl + Cl → Cl₂

(iii) Sodium peroxide: After Na metal is gotten from Downs process, it is heated on Aluminium trays in presence of air(without CO₂) to form Sodium peroxide.

2Na + O_2(air) → Na₂O₂

(iv) Sodium carbonate: Sodium hydrogen carbonate is obtained as a precipitate by reacting sodium chloride with ammonium hydrogen carbonate. The resultant crystals can be heated to obtain Sodium Carbonate.

2NH₂ + H₂O → (NH₄)₂CO₃

(NH₄)₂CO₃ + H₂O + CO₂ → 2NH₄HCO₃

2NH₄HCO₃ + NaCl → NH₄Cl + NaHCO₃

The resultant crystals can be heated to obtain Sodium Carbonate.

2NaHCO₃ → Na₂CO₃+ CO₂ + H₂O