Home
Class 12
CHEMISTRY
In Hall's process for the preparation of...

In Hall's process for the preparation of `Al,` graphite anode has a long life.

Text Solution

Verified by Experts

The correct Answer is:
F
Molten `Al_(2)O_(3)+Na_(3)AlF_(6)(` Cryolite `)+CaF_(2)(` Fluorspar`)+AlF_(3)` is used.
The electrolysis of this mixture is carried out using carbon `(` graphit `)` electrodes. The `O_(2)` liberated at the anode reacts with the graphite anode producing `CO` and `O_(2)`. Thus, a graphit anode needs to be replaced periodically.
Thus, graphite anodes do not have long life.
The overall reactions are as follows`:`
Cathode `:Al^(+3)(melt)+3e^(-) rarr Al^(l)`
Anode `:C(s)+O^(2-)(melt) rarr CO(g)+2e^(-)`
`C(s)+2O^(2-)(melt) rarr CO_(2)(g)+4e^(-)`
Promotional Banner

Similar Questions

Explore conceptually related problems

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

Draw labelled diagram of Hall-Heroult electrolytic cell for the extraction of aluminium write anode and cathode reactions.

Name the chemical process involved in the preparation of ethanol.

Draw a neat labelled diagram of electrolytic cell used in the extraction of Aluminium by Hall - Heroult Process. Write the reactions take place at cathode and anode.

Which one of the following has haplontic life cycle

If the half life period for a reaction in A is 100 min . How long will it take [A] to reach 25 % of its initial concentration ?