$$ \text { Match the following } $$

$$ \begin{array}{llll} \hline & \text { List-I (Process) } & & \text { List-II (Metal) } \\ \hline \text { (A) } & \text { Hall-Heroult process } & \text { (I) } & \mathrm{Ti} \\ \hline \text { (B) } & \text { Mond process } & \text { (II) } & \mathrm{In} \\ \hline \text { (C) } & \text { van-Arkel process } & \text { (III) } & \mathrm{Al} \\ \hline \text { (D) } & \text { Zone refining process } & \text { (IV) } & \mathrm{Ni} \\ \hline \end{array} $$

The correct answer is

Which of the following reactions is an example of roasting?

Consider the following.

Statement-I In the extraction of Al by Hall-Heroult process, pure $\mathrm{Al}_2 \mathrm{O}_3$ mixed with $\mathrm{Na}_3 \mathrm{AlF}_6$ lowers its melting point and increases conductivity.

Statement-II Zirconium metal is purified by zone refining method.

Which of the following is used as froth stabilizer in froth floatation process?