The correct option is **B. Contact process**. ### Detailed Explanation The Contact Process is the primary method used for the industrial production of sulfuric acid (H₂SO₄). This process is significant not only for its role in producing one of the most important industrial chemicals but also for its environmental implications, particularly due to the emissions of sulfur dioxide (SO₂). #### Steps of the Contact Process: 1. **Sulfur Combustion**: The process begins with the combustion of sulfur or sulfide ores (like pyrite) to produce sulfur dioxide (SO₂): \[ S + O_2 \rightarrow SO_2 \] 2. **Conversion to Sulfur Trioxide**: The sulfur dioxide is then oxidized to sulfur trioxide (SO₃) using oxygen in the presence of a catalyst (usually vanadium(V) oxide, V₂O₅) at high temperatures (around 450°C) and pressures (2-3 atmospheres): \[ 2SO_2 + O_2 \xrightarrow{V_2O_5} 2SO_3 \] 3. **Formation of Sulfuric Acid**: The sulfur trioxide is then absorbed in water to form sulfuric acid. However, this step is not done directly because SO₃ reacts violently with water. Instead, it is typically absorbed in existing sulfuric acid to form oleum (H₂S₂O₇), which can then be mixed with water to produce sulfuric acid: \[ SO_3 + H_2O \rightarrow H_2SO_4 \] #### Environmental Impact The environmental impact of the Contact Process primarily stems from the emission of sulfur dioxide, which can contribute to air pollution and acid rain. When sulfur dioxide is released into the atmosphere, it can react with water vapor to form sulfurous acid (H₂SO₃) and eventually sulfuric acid, leading to acid rain that can harm ecosystems, buildings, and human health. ### Why Other Options Are Incorrect - **A. Haber Process**: This process is used to synthesize ammonia (NH₃) from nitrogen (N₂) and hydrogen (H₂) gases. It is crucial for fertilizer production but is not related to sulfuric acid production. - **C. Ostwald Process**: This process is used to produce nitric acid (HNO₃) from ammonia. It involves the oxidation of ammonia to nitric oxide (NO), which is then further oxidized to nitrogen dioxide (NO₂) and subsequently converted to nitric acid. While it is an important industrial process, it does not produce sulfuric acid. - **D. Solvay Process**: This process is used for the production of sodium carbonate (soda ash) from sodium chloride (NaCl) and limestone (CaCO₃). It is not related to sulfuric acid production and focuses on a different chemical compound entirely. ### Summary of Key Points - The **Contact Process** is the primary method for producing sulfuric acid, involving the oxidation of sulfur dioxide to sulfur trioxide. - The process has significant environmental impacts due to sulfur dioxide emissions, contributing to air pollution and acid rain. - Other processes listed (Haber, Ostwald, Solvay) are unrelated to sulfuric acid production and focus on different chemicals. - Understanding the Contact Process is crucial for recognizing its industrial importance and environmental implications. This thorough understanding of the Contact Process and its context will help you in your studies and exams related to industrial chemistry and environmental science.