JEE Main202330 Jan 2023Evening ShiftChemistryGeneral Principles and Processes of Isolation of MetalsActual
Given below are two statements: Statement I: During Electrolytic refining, the pure metal is made to act as anode and its impure metallic form is used as cathode. Statement II: During the Hall-Heroult electrolysis process, purified Al 2 O 3 is mixed with Na 3 AlF 6 to lower the melting point of the mixture. In the light of the above statements, choose the most appropriate answer from the options given below:
Options
- AStatement I is incorrect but Statement II is correct
- BBoth Statement I and Statement II are incorrect
- CStatement I is correct but Statement II is incorrect
- DBoth Statement I and Statement II are correct
Correct answer
A. Statement I is incorrect but Statement II is correct
Step-by-step solution
In Electrolytic refining, the pure metal is used as cathode and impure metal is used as anode. Electrolytic refining of aluminium is called Hall-Heroult process. Na 3 AlF 6 is added during electrolysis of Al 2 O 3 to lower the melting point and increase conductivity. Reactions at cathode and anode are as follows: Cathode: Al 3 + ( melt )   +   3 e -   →   Al ( l ) Anode: C ( s )   +   O 2 -   ( melt )   →   CO ( g )   +   2 e - C ( s )   +