Corundum and cryolite are important ores of which of the following?

Correct answer: (a) Aluminium

Explanation

Corundum (Al₂O₃) and cryolite (Na₃AlF₆) are both important ores of aluminium.

Cryolite acts as a flux that lowers the melting point in the Hall-Héroult process for extracting aluminium.

Corundum is extremely hard (next to diamond on the Mohs scale); its varieties include ruby and sapphire.