Manufacture of Sodium by Electrolysis of Fused NaCl

Electrolysis is the process of decomposition of a compound using electricity. Sodium is manufactured by electrolysis of fused NaCl.

Process:
1. Electrolysis of fused NaCl is done in a Downs cell. It consists of a rectangular container made of iron and lined with firebrick.
2. The cell is divided into two compartments by a porous partition, which allows ions to pass through it but prevents mixing of the two solutions.
3. The anode is made of graphite and the cathode is made of iron.
4. Sodium chloride is melted and fused at a temperature of about 800°C to form molten NaCl.
5. When an electric current is passed through the molten NaCl, it dissociates into its constituent ions, Na+ and Cl-.
6. The positively charged sodium ions move towards the cathode, which is negatively charged. At the cathode, sodium ions gain electrons and are converted to sodium metal, which is collected at the bottom of the cell.
7. The negatively charged chloride ions move towards the anode, which is positively charged. At the anode, chloride ions lose electrons and are converted to chlorine gas, which is collected at the top of the cell.
8. The overall reaction can be represented as:
2NaCl(l) → 2Na(l) + Cl2(g)

Answer:
Thus, the correct answer is option 'B', i.e., Na is manufactured by electrolysis of fused NaCl.