Question

Cryolite is used in the electrolytic of aluminium, because :
 A. it dissolves alumina
 B. it dissolves sodium
 C. it dissolves aluminium fluoride
 D. it decreases the solubility

Answer 1

Hint According to the question, first we should dissolve each and every optional ore. Then only we will reach the conclusion that which one will dissolve in this reaction.

Complete solution:
  Cryolite is used in the electrolytic of aluminium because it dissolves alumina $A{l_2}{O_3}$ is used along with fluorspar and cryolite. Cryolite is used because it reduces the melting temperature of the mixture and also acts as a solvent to help in dissolving alumina.
 Bauxite, which is an Aluminium ore, is purified to yield a white powder- alumina (also known as aluminium oxide), from which aluminium can be extracted. The extraction of aluminium is done by the Electrolysis Process. In this process, Alumina must be melted so that electricity can pass through it. This electrolytic process is very expensive.
 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.
Hence, the correct option is (A.) it dissolves alumina.

Note: Alumina, additionally called aluminum oxide, artificially created aluminum oxide $A{l_2}{O_3}$ a white or almost lackluster glasslike substance that is utilized as a beginning material for the purifying of aluminum metal. It additionally fills in as the crude material for an expansive scope of cutting edge fired items and as a functioning specialist in compound handling.