What happens in the purifying chamber in contact process?

Dust particles are removed

The correct answer is option 2. Dust particles are removed.

In the purifying chamber in the contact process for sulfuric acid production, several key steps occur to ensure the purification of the gases before they enter the catalyst chamber. Among the options provided the correct answer is dust particles are removed

Removal of Impurities: The gases entering the purifying chamber may contain impurities such as dust particles, sulfur dioxide \((SO_2)\), and nitrogen oxides \((NOx)\). To ensure the effectiveness of the catalytic reaction and prevent catalyst poisoning, these impurities must be removed.

Scrubbing or Washing: In the purifying chamber, the gases are typically passed through scrubbers or wash towers containing a suitable absorbent, such as water or sulfuric acid. These absorbents help to trap and remove dust particles, as well as other impurities, from the gases. Dust particles and other solid impurities are often removed through filtration or settling processes within the scrubbers.

Drying of Gases: While the main purpose of the purifying chamber is to remove impurities, it may also include provisions for drying the gases. This drying process helps ensure that the gases entering the catalyst chamber are free from moisture, which could interfere with the catalytic reaction. However, the specific method of drying (such as using a spray of HCl) may vary depending on the design of the sulfuric acid production plant.

Heating: While heating may occur in various stages of the contact process, including the purifying chamber, it is primarily used to optimize reaction conditions rather than for purification purposes. Heating helps maintain the gases at the appropriate temperature range for the catalytic reaction to occur efficiently.

In the purifying chamber of the contact process, the main focus is on removing impurities such as dust particles and other contaminants from the gases before they enter the catalyst chamber. This ensures the effectiveness of the catalytic reaction and helps prevent catalyst poisoning. While drying of gases may occur as part of the purification process, the primary purpose is impurity removal.

Therefore, the correct option is:2. Dust particles are removed.