Problem 55 - A Complete Resource Book in Chemistry for JEE Main

Question

Which catalyst is used in the manufacture of sulphuric acid by Contact Process? (a) Ni powder (b) Platinized asbestos (c) anhydrous \(\mathrm{Al}_{2} \mathrm{O}_{3}\) (d) Al powder

Step-by-Step Solution

Answer

Platinized asbestos (b) is used as a catalyst in the Contact Process.

Step 1: Understanding the Contact Process

The Contact Process is an industrial method used to produce sulfuric acid (H_2SO_4). It involves the oxidation of sulfur dioxide (SO_2) to sulfur trioxide (SO_3), followed by the absorption of SO_3 in water.

Step 2: Role of Catalyst in the Contact Process

In the Contact Process, a catalyst is used to increase the rate of the conversion of sulfur dioxide (SO_2) to sulfur trioxide (SO_3). The catalyst allows the reaction to proceed at a faster rate and at lower temperatures than would be possible without it.

Step 3: Identifying the Correct Catalyst

The most common and effective catalyst used in the Contact Process is vanadium(V) oxide (V_2O_5). However, the options given do not include vanadium(V) oxide. Platinized asbestos is historically used as a catalyst in this context, before vanadium(V) oxide became the preferred choice due to cost and effectiveness.

Step 4: Selecting the Best Option

Since the four options provided do not include vanadium(V) oxide (V_2O_5), the best choice from the given options is platinized asbestos, as it has been used in the past for this process before the adoption of V_2O_5.

Key Concepts

Sulphuric Acid

Sulphuric acid, with the chemical formula \(H_2SO_4\), is one of the most important compounds in industrial chemistry. It is a highly corrosive, dense, and oily liquid that plays a crucial role in numerous industrial processes. The Contact Process is the most common industrial method to produce sulphuric acid due to its efficiency and cost-effectiveness.

• The Contact Process involves the conversion of sulfur dioxide \(SO_2\) into sulfur trioxide \(SO_3\), followed by the absorption of \(SO_3\) into water to form sulphuric acid.
• This process is favored for its ability to produce highly concentrated \(H_2SO_4\).

Sulphuric acid is a key component in the manufacturing of fertilizers, particularly phosphate fertilizers. It's also used in refining petroleum, processing metals, and in the production of chemicals such as hydrochloric acid and nitric acid.

Catalyst

A catalyst is a substance that speeds up a chemical reaction without being consumed in the process. In the context of the Contact Process, a catalyst plays an essential role in converting sulfur dioxide \(SO_2\) to sulfur trioxide \(SO_3\).

• Catalysts lower the activation energy needed for reactions, allowing them to occur faster and often at lower temperatures.
• By using a catalyst, manufacturers can enhance production efficiency and reduce energy consumption.

In the Contact Process, the catalyst helps in achieving a high conversion rate of \(SO_2\) to \(SO_3\), which directly affects the overall yield and efficiency of sulphuric acid production.

Vanadium(V) oxide

Vanadium(V) oxide \(V_2O_5\) is the most widely used catalyst in the Contact Process today. It replaced earlier catalysts such as platinized asbestos due to its cost-effectiveness and efficiency. Its ability to operate effectively at lower temperatures than other catalysts makes it the catalyst of choice.

• Vanadium(V) oxide helps in the oxidation of \(SO_2\) to \(SO_3\) by providing a surface for the reaction to take place.
• It facilitates a higher rate of conversion even at temperatures as low as 400°C, significantly lower than what would be required without a catalyst.

This reduces the operational costs and also minimizes equipment wear and tear due to lower thermal stress.

Industrial Chemistry

Industrial chemistry involves the large-scale production of chemicals and materials that are used in everyday life. Sulphuric acid production through the Contact Process is a quintessential example of industrial chemistry at work.

• Industrial chemistry is focused on optimizing chemical processes to increase efficiency, reduce costs, and minimize environmental impact.
• The selection of catalysts, like vanadium(V) oxide in the Contact Process, is critical to achieving these goals.

Understanding industrial chemistry principles allows industries to innovate in processes such as refining, metallurgy, and pharmaceuticals, thereby advancing technological progress while keeping sustainability in mind.