Question

Aluminium is dissolved in-------- to make a conducting solution.
during hall heroult's process

Answer 1

Ans is molten cryolite 
Aluminium is dissolved in  molten cryolite 
  to make a conducting solution.

Answer 2

The answer for your question is flourospar and cryolite.
It is really alumina not aluminium (in your question)
Aluminium is obtained from Alumina, it's ore.

Good luck for your chemistry exam of tomorrow