Question

why is cryollite added in the electrolysis of alumina?​

Answer 1

Answer:

The mixture of cryolite and aluminium oxide has a lower melting point than pure aluminium oxide. This means a lower amount of energy is required to establish effective conditions for electrolysis and thus makes it more cost effective.

Answer 2

Explanation:

Instead, it is dissolved in molten cryolite – an aluminium compound with a lower melting point than aluminium oxide. The use of molten cryolite as a solvent reduces some of the energy costs involved in extracting aluminium by allowing the ions in aluminium oxide to move freely at a lower temperature.