Read the passage carefully and answer the questions.

The transition metals and their compounds are known for their catalytic activity. This activity is ascribed to their ability to adopt multiple oxidation states and to form complexes. Vanadium(V) oxide (in Contact Process), finely divided iron, and nickel (in Catalytic Hydrogenation) are some of the examples. Catalysts at a solid surface involve the formation of bonds between reactant molecules and atoms of the surface of the catalyst (first row transition metals utilise 3d and 4s electrons for bonding). This has the effect of increasing the concentration of the reactants at the catalyst surface and also weakening of the bonds in the reacting molecules (the activation energy is lowering). Also because the transition metal ions can change their oxidation states, they become more effective as catalysts.

Which of the following catalyses the oxidation of $SO_2$ in the manufacture of sulphuric acid?

Vanadium(V) oxide

The correct answer is Option (1) → Vanadium(V) oxide

In the Contact Process for manufacturing sulfuric acid, $SO_2$ is oxidized to $SO_3$ using a catalyst.

(i) Production of $SO_2$:

$S + O_2 \overset{\text{Burn}}{\longrightarrow} SO_2$

Or $4FeS_2 + 11O_2 \overset{\text{Roasting}}{\longrightarrow} 2Fe_2O_3 + 8SO_2$

(ii) Oxidation of $SO_2$ to $SO_3$:

(iii) Conversion of $SO_3$ into $H_2SO_4$:

$SO_{3} + \underset{(\text{conc.})}{H_2SO_4} \longrightarrow \underset{(\text{Oleum})}{H_2S_2O_7}$

$H_2S_2O_7 + H_2O \longrightarrow 2H_2SO_4$

Explanation

Option 1: Vanadium(V) oxide

Vanadium(V) oxide ($V_2O_5$) is the catalyst used in the Contact Process. It facilitates the oxidation of $SO_2$ to $SO_3$ by alternating between oxidation states.

Option 2: Finely divided iron

Iron is used as a catalyst in the Haber process for ammonia synthesis, not in sulphuric acid manufacture.

Option 3: Nickel

Nickel is used in catalytic hydrogenation of oils and alkenes, not in $SO_2$ oxidation.

Option 4: Vanadium(II) oxide

This is not used in the Contact Process and does not act as the required oxidation catalyst.