Everyday chemistry (bleaching): Identify the most commonly used bleaching agent in household/industrial applications. Consider agents historically and currently used for decolorizing and disinfecting. Choose the correct option.

Concept
Bleaching is commonly effected by strong oxidizers. Historically and widely, chlorine (and its compounds like bleaching powder/sodium hypochlorite) has been the most commonly used bleaching agent for textiles and water disinfection.

Why not others?

• SO₂ is a reducing agent used in specific food/textile contexts, not the most common overall.
• H₂S is malodorous/toxic and not a bleaching agent.
• O₃ is a potent oxidizer but specialized and less common than chlorine systems.

Final Answer
Chlorine (Cl₂)