1.

In the extraction of Aluminium by electrolysis. (i) Write overall cell reaction.(ii) What is the role of cryolite?

Answer»

i) At cathode - Al+3 (melt) + 3e- → Al(l)

At anode - C(s) + O2- (melt) → Co(g) + 2e-

C(s) + 2O2- (melt) → CO2 (g) + 4e-

ii) Cryolite (Na3Al F6) makes Alumina good conductor of electricity and lowers the melting (fusion) + temperature of Alumina.

(i)

2Al2O3 + 3C → 4Al + 3CO2

Al2O3 \(\overset{electrolysis}{\longrightarrow}\) 2Al3 + 3O2-

(ii)

Cryolite lowers the melting point of the mixture and increases the conductivity.



Discussion

No Comment Found

Related InterviewSolutions