Chemistry - Metallurgy Question with Solution | TestHub

(A) The reduction of ${\mathrm{Al}}_2{\mathrm{O}}_3$ with coke $\left(\mathrm{C}\right)$ at a temperature $>2500 °\mathrm{C}$ is not carried out due to the formation of carbides.

(B) It is correct as neutralisation of aluminate solution is done by passing ${\mathrm{CO}}_2$ gas to precipitate hydrated alumina.

(C) Reaction of powdered one is carried out with hot concentrated $\mathrm{NaOH}$ at $473 \mathrm{K}-523 \mathrm{K}$ and $35-36$ bar pressure.

(D)Aluminium In the metallurgy of aluminium, purified Al₂O₃ is mixed with ${\mathrm{Na}}_3{\mathrm{AlF}}_6$ or CaF₂ which lowers the melting point of the mixture and brings conductivity.Thus electrolysis of the molten mass is carried out in an electrolytic cell using carbon electrodes. The oxygen liberated at anode reacts with the carbon of anode producing CO and CO₂ and Al at the cathode.