A corrosive gas from burning coal often associated with industrial smog is

A corrosive gas from burning coal often associated with industrial smog is

• A. CO
• B. CO2
• C. SO2
• D. NO2

Answer: (C)

Coal contains sulfur, and when it is burned that sulfur is released as sulfur dioxide. This gas is corrosive to metals and fabrics and, in the atmosphere, reacts with water vapor to form sulfurous and sulfuric acids. Those acidic aerosols are a key part of industrial smog (the so-called London-type smog) produced by coal combustion. That makes sulfur dioxide the gas most closely associated with corrosive industrial smog. The other gases aren’t the primary corrosive smog component from coal: carbon monoxide is toxic but not the corrosive smog agent here, carbon dioxide is not corrosive, and nitrogen dioxide is linked more to photochemical smog rather than the classic corrosive industrial smog from coal.

Coal contains sulfur, and when it is burned that sulfur is released as sulfur dioxide. This gas is corrosive to metals and fabrics and, in the atmosphere, reacts with water vapor to form sulfurous and sulfuric acids. Those acidic aerosols are a key part of industrial smog (the so-called London-type smog) produced by coal combustion. That makes sulfur dioxide the gas most closely associated with corrosive industrial smog. The other gases aren’t the primary corrosive smog component from coal: carbon monoxide is toxic but not the corrosive smog agent here, carbon dioxide is not corrosive, and nitrogen dioxide is linked more to photochemical smog rather than the classic corrosive industrial smog from coal.