Applications of Chlorine

Applications of Chlorine

1. Bleach (NaClO)

   • 2NaOH + Cl2 --> NaClO + NaCl + H2O
     • DISPROPORTIONATION REACTION - chlorine is oxidised and reduced

2. Water Treatment

   • Cl2 + H20 --> 2H+ + Cl- + ClO-
     • chlorate(I) ions kill bacteria
     • Cl2 + H2O --> HOCl + HCl
       • H0Cl -sunlight-> O2 + 2HCl
   • Cl2 + H2O --> 4H+ + Cl- + O2
   • POSITIVES
     • kills pathogens
     • some chlorine doesn't react until later, preventing reinfection further on
     • prevents growth of algae and discolouration caused by organic compounds
     • removes bad tastes and smells
   • NEGATIVES
     • chlorine gas is very harmful if inhaled
     • liquid chlorine can cause severe chemical burns
     • can react with organic compounds in water to form chlorinated hydrocarbons which are carcinogenic
       • e.g. CH3Cl
       • however, increased cancer risk is small compared to risks from untreated water