What is the catalyst used in the manufacture of sulphuric acid by contact process? (a) Ni powder (b) Platinised asbestos (c) Anhydrous \(\mathrm{Al}_{2} \mathrm{O}_{3}\) (d) Al powder

The Contact Process is a critical industrial procedure for creating sulfuric acid, which is essential in a wide array of industries, including the manufacture of fertilizers, chemicals, and petroleum products. At its core, the Contact Process converts sulfur dioxide into sulfur trioxide, which is then transformed into sulfuric acid.

Understanding the Contact Process begins with the combustion of sulfur or sulfide ores to produce sulfur dioxide (SO2). The next step is vital: the oxidation of sulfur dioxide into sulfur trioxide (SO3). This stage requires carefully controlled conditions, including a specific temperature range and pressure, to ensure efficiency and safety.

What makes the Contact Process especially effective is its energy-saving design. It recirculates the heat generated in the oxidation step to preheat incoming gases, thereby conserving energy. The production of high-concentration sulfuric acid through this process is both cost-effective and environmentally favorable, as it minimizes waste and optimizes energy usage.

Diving deeper into the Contact Process, the oxidation of sulfur dioxide (SO2) to sulfur trioxide (SO3) is a pivotal step that determines the overall yield and efficiency of sulfuric acid production. This oxidation is an exothermic reaction, which means it releases a considerable amount of energy in the form of heat.

The reaction is typically represented by the chemical equation:
\[ 2 \text{SO}_2(g) + \text{O}_2(g) \rightarrow 2 \text{SO}_3(g) \]
However, the reaction is not straightforward; it proceeds slowly and requires high energy to take place without a catalyst. This is where a catalyst plays an essential role, enhancing the rate of the reaction significantly while allowing it to occur at lower temperatures, thus conserving energy and improving throughput.

In the presence of a catalyst, the sulfur dioxide and oxygen molecules absorb energy, which helps them overcome the activation energy barrier and facilitates the formation of sulfur trioxide. The catalyst does not get consumed in the reaction, allowing it to be used repeatedly, which underscores its economic advantage in the large-scale industrial process.

Vanadium(V) oxide, chemically denoted as V2O5, is the preferred catalyst used in the Contact Process for the manufacture of sulfuric acid. Vanadium(V) oxide’s high effectiveness stems from its ability to provide a surface for the sulfur dioxide and oxygen to come together, which facilitates their interaction and the subsequent reaction to form sulfur trioxide.

The choice of V2O5 as a catalyst in the reaction is attributed to its ability to withstand the high temperatures involved in the process without breaking down. Furthermore, it remains unchanged after the reaction, making it an efficient and cost-effective catalyst for continuous use in the industrial process. Also, unlike other potential catalysts, vanadium(V) oxide retains its catalytic properties over multiple cycles of the production process, requiring only occasional regeneration to restore its full efficiency.