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 In the context of the Hall - Heroult process for the extraction of Al, which of the following statements is false ?

  • Option 1)

    CO and CO2 are produced in this process
     

     

  • Option 2)

    Al2O3 is mixed with CaF2 which lowers the melting point of the mixture and brings conductivity

  • Option 3)

     Al3+ is reduced at the cathode to form Al

     

  • Option 4)

    Na3AlF6 serves as the electrolyte

 

Answers (1)

As we learnt in

Hall and Heroult Process -

Use to extract aluminium. A fuse mixture of alumina (20%), cryolite (60%) and fluorspar (20%) is electrolysed using carbon electrodes.

- wherein

Cryolite makes Al2O3 conducting, fluorspar decreases the melting point of alumina

 

In Hall and Heroult process, cryolite is added to make Al_{2}O_{3} conducting, cryolite is a common name for  Na_{3}AlF_{6}

 


Option 1)

CO and CO2 are produced in this process
 

 

This option is incorrect.

Option 2)

Al2O3 is mixed with CaF2 which lowers the melting point of the mixture and brings conductivity

This option is incorrect.

Option 3)

 Al3+ is reduced at the cathode to form Al

 

This option is incorrect.

Option 4)

Na3AlF6 serves as the electrolyte

This option is correct.

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Vakul

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