Match List-I with List-II: | List-I (Mineral) | List-II (Metal)... | Agrigyan

The Van Arkel method is a vapour phase refining technique used for removing all oxygen and nitrogen impurities from metals like Zirconium ($\text{Zr}$) and Titanium ($\text{Ti}$):

$$\text{Zr (impure)} + 2\text{I}_2 \xrightarrow{870\text{ K}} \text{ZrI}_4\text{ (volatile)}$$ $$\text{ZrI}_4 \xrightarrow{2075\text{ K, Tungsten filament}} \text{Zr (pure)} + 2\text{I}_2$$

Nickel ($\text{Ni}$) is refined by the Mond process, Copper ($\text{Cu}$) by electrolytic refining, and Tin ($\text{Sn}$) by liquation.

Thermal stability of hydrides of Group 16 elements ($\text{H}_2\text{E}$) depends on the bond dissociation enthalpy of the $\text{E-H}$ bond. As the size of the central atom increases down the group from oxygen to polonium:

$$\text{O} \lt \text{S} \lt \text{Se} \lt \text{Te} \lt \text{Po}$$

The $\text{E-H}$ bond length increases and the bond dissociation energy decreases. Consequently, thermal stability decreases down the group:

$$\text{H}_2\text{Po} \lt \text{H}_2\text{Te} \lt \text{H}_2\text{Se} \lt \text{H}_2\text{S} \lt \text{H}_2\text{O}$$

In terms of the letters: (C) < (D) < (B) < (E) < (A).

Matching chemicals with their commercial manufacturing processes:

• Ammonia ($\text{NH}_3$): Synthesized by the Haber process from $\text{N}_2$ and $\text{H}_2 \rightarrow$ (A)-(IV).
• Chlorine ($\text{Cl}_2$): Manufactured by the oxidation of $\text{HCl}$ by atmospheric oxygen in the Deacon process $\rightarrow$ (B)-(III).
• Sulphuric Acid ($\text{H}_2\text{SO}_4$): Manufactured on a large scale by the Contact process using $\text{V}_2\text{O}_5$ catalyst $\rightarrow$ (C)-(II).
• Nitric Acid ($\text{HNO}_3$): Manufactured by catalytic oxidation of ammonia in the Ostwald process $\rightarrow$ (D)-(I).