Question

What type of reaction is taking place when chlorine acts as a bleaching agent?

Answer 1

• Oxidation reaction is responsible for the process of bleaching.
• Bleaching occurs in the presence of moisture.
• Chlorine reacts with water to form Hydrochloric acid$\left(\mathrm{HCl}\right)$ and Hypochlorous acid$\left(\mathrm{HOCl}\right)$.
  $\underset{\mathrm{Chlorine}\mathrm{gas}}{{\mathrm{Cl}}_2\left(\mathrm{g}\right)}+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\to \underset{\mathrm{Hydrochloric}\mathrm{Acid}}{\mathrm{HCI}\left(\mathrm{aq}\right)}+\underset{\mathrm{Hypochlorous}\mathrm{Acid}}{\mathrm{HOCl}\left(\mathrm{aq}\right)}$
• $\mathrm{HOCl}$ is unstable, and it quickly dissociates into Hydrochloric acid$\left(\mathrm{HCl}\right)$ and nascent oxygen or free oxygen.
  $\mathrm{HOCl}\left(\mathrm{aq}\right)\to \mathrm{HCl}\left(\mathrm{aq}\right)+\underset{\mathrm{Nascent}\mathrm{Oxygen}}{\left[\mathrm{O}\right]}$
• Nascent oxygen is a powerful oxidizing agent. Its formation is responsible for the bleaching nature of Chlorine in the presence of moisture.