In the contact process for the industrial manufacture of sulfuric acid, which chemical substance is employed as the primary catalyst in the catalytic oxidation of sulfur dioxide to sulfur trioxide?

💡 Solution & Explanation

Vanadium pentoxide serves as the active catalyst in the exothermic conversion of sulfur dioxide to sulfur trioxide during the contact process for producing sulfuric acid. Finely divided nickel is commonly used in fat hydrogenation, whereas manganese dioxide acts as a catalyst in laboratory oxygen preparation. Platinum was historically used but was replaced by vanadium pentoxide because it is less susceptible to catalytic poisoning by impurities.