Reactions of Chlorine
- A disproportionation reaction is a reaction in which the same species is both oxidised and reduced
- The reaction of chlorine with water and cold, dilute aqueous alkali are examples of disproportionation reactions
- In these reactions, the chlorine gets oxidised and reduced at the same time
The reaction of chlorine with water
- Chlorine can be used to clean water and make it drinkable
- The reaction of chlorine in water is a disproportionation reaction in which the chlorine gets both oxidised and reduced
The disproportionation reaction of chlorine with water in which chlorine gets reduced to HCl and oxidised to HClO
- Chloric(I) acid (HClO) sterilises water by killing bacteria
- Chloric acid can further dissociate in water to form ClO- (aq):
HClO (aq) → H+ (aq) + ClO- (aq)
- ClO-(aq) also acts as a sterilising agent cleaning the water
- If some universal indicator is added to the solution it will first turn red due to the acidity of both reaction products. It will then turn colourless as the HClO bleaches the colour.
The reaction of chlorine with cold, dilute aqueous sodium hydroxide
- The reaction that takes place is:
- The ionic equation is:
- The ionic equation shows that the chlorine gets both oxidised and reduced
- Chlorine gets oxidised as there is an increase in ox. no. from 0 to +1 in ClO-(aq)
- The half-equation for the oxidation reaction is:
- Chlorine gets reduced as there is a decrease in ox. no. from 0 to -1 in Cl-(aq)
- The half-equation for the reduction reaction is:
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The mixture of NaCl and NaClO (sodium chlorate (I)) is used as Bleach and to disinfect/ kill bacteria