Question

By dissolving aluminium oxide in cryolite, a ______ solution is produced.

Options

• conducting

• non-conducting

Answer 1

By dissolving aluminium oxide in cryolite, a conducting solution is produced.

Explanation:

Pure aluminium oxide (alumina) has an extremely high melting point (over 2000°C) and is a very poor conductor of electricity on its own. Dissolving it in molten cryolite (Na₃AlF₆) significantly lowers the mixture’s melting point to about 950°C and releases mobile sodium, aluminium, and fluorine ions. This creates a highly conducting electrolytic bath that allows electric current to flow efficiently during the Hall-Héroult extraction process.