Castner Kellner cell

The Castner Kellner cell is an electrolytic cell that is used to produce sodium metal by the electrolysis of sodium chloride. The cell consists of a cathode and an anode separated by a diaphragm. The electrolyte used in the cell is an aqueous solution of sodium chloride.

Electrolyte used in Castner Kellner cell

The correct answer is option 'C', which is an aqueous solution of sodium chloride. The reason for using a sodium chloride solution is that sodium chloride has a low melting point and can be easily melted to form a molten state. The molten sodium chloride is then electrolyzed to produce sodium metal and chlorine gas.

Other options

Option 'A', which is an aqueous solution of sodium hydroxide, cannot be used as the electrolyte in the Castner Kellner cell as the electrolysis of sodium hydroxide produces hydrogen gas and oxygen gas instead of sodium metal.

Option 'B', which is a sodium amalgam, is not an electrolyte but rather a product of the electrolysis of sodium chloride. Sodium amalgam is produced at the cathode of the cell and is used to extract sodium metal.

Option 'D', which is an aqueous solution of sodium bromide, cannot be used as the electrolyte in the Castner Kellner cell as the electrolysis of sodium bromide produces bromine gas instead of sodium metal.

Aqueous alkali chloride solution (usually sodium chloride solution) to produce the corresponding alkali hydroxide