Chlorination is a process used for water purification. The disinfecting action of chlorine is mainly due to

1. Chlorination is a widely used method for the disinfection step in water purification. 2. When elemental chlorine (Cl2) is added to water, it undergoes hydrolysis: Cl2 + H2O ⇌ HOCl + HCl. 3. This reaction forms both hypochlorous acid (HOCl) and hydrochloric acid (HCl). 4. Hypochlorous acid (HOCl) is a potent oxidizing agent and is the primary active chemical species responsible for the disinfecting action of chlorine in water. It effectively kills bacteria and other harmful microorganisms. 5. While hydrochloric acid is also formed (Option A), it is a strong acid but does not possess the significant disinfecting properties of HOCl in this context. 6. The formation of nascent oxygen (Option C) or hydrogen (Option D) is not the main mechanism of chlorine disinfection. 7. Therefore, the formation of hypochlorous acid is the principal reason for chlorine's effectiveness in water purification. Option (B) is correct.