Other Sulfur containing Compounds

Perhaps the most significant compound of sulfur used in modern industrialized societies is sulfuric acid (H2SO4). Sulfur dioxide (SO2) finds practical applications in bleaching and refrigeration but it is also a nuisance gas resulting from the burning of sulfurous coals. Sulfur dioxide gas then reacts with the water vapor in the air to produce a weak acid, sulfurous acid (H2SO3

) which contributes to the acid rain problem.

• Sulfuric acid, H₂SO₄, is produced by reacting SO3

• with water. However, this often leads to pollution problems. SO₃(g) is reacted with 98% H₂SO₄ in towers full of ceramic material to produce H₂S₂O₇ or oleum. Water is circulated in the tower to maintain the correct concentration and the acid is diluted with water at the end in order to produce the correct concentration. Pure sulfuric acid has no color and odor, and it is an oily, hygroscopic liquid. However, sulfuric acid vapor produces heavy, white smoke and a suffocating odor.
• Dilute sulfuric acid, H₂SO₄(aq) reacts with metals and acts as a strong acid in common chemical reactions. It is used to produce H₂(g) and liberate CO₂(g) and can neutralize strong bases.
• Concentrated sulfuric acid, H₂SO₄ (conc.) has a strong affinity for water. In some cases, it removes H and O atoms. Concentrated sulfuric acid is also a good oxidizing agent and reacts with some metals.

(Concentrated sulfuric acid used in forward reaction to remove H and O atoms.)