Chlorine gas dissolves to some extent in water and form hydrochloric acid and hypochlorous acid as products. Therefore, an acidic solution is given when products are formed. This reaction is a dangerous one because chlorine gas is a toxic gas.
Written by: Heshan Nipuna, updated:2020/05/18
Reaction between chlorine gas and water is a reversible reaction. Therefore, all dissolved chlorine gas does not react with water. Hence, unreacted chlorine will remain in the aqueous solution. After treating chlorine gas to water, , check the pH value of aqueous solution. You may see, pH value will be lower than seven. If you send more chlorine gas, pH value will be reduce more due to formation of more HCl and HOCl.
Solubility of chlorine depends on the temperature. Therefore, amount of given products also depend on the temperature too. At lower temperature, solubility of chlorine is great and gives higher yield.
Hydrochloric acid (HCl) is a strong acid and hypochlorous acid (HOCl) is a weak acid. Due to existance of hydrochloric acid, dissociation of hypochlorous acid is reduced. Both acids are soluble in water.
Get a partially filled container by distilled water (to have a free air space). Container should be completely sealed and closed on top to avoid gases are leaked to outside from the container. When you treat chlorine gas to the distilled water in that container, there will be several equilibriums in several phases.
One chlorine mole reacts with one water mole and produce one mole of HCl and one mole of HOCl respectively.
Oxidation number of chlorine is changed during the reaction. Therefore, this reaction is a redox reaction. Chlorine is at 0 oxidation state in chlorine gas.
Here we are going to see how other halogens will react with water.
You should extremely careful about safety of you can other when you are doing experiment with chlorine gas. If you inhale chlorine gas, it will react with water in the mucous/linings of your lungs and form hydrochloric acid. This will destroy your lung's ability to take in oxygen and will be very painful and may cause to the death too.
This reaction produces hypochlorous acid as a product. Hypochlorous acid (HOCl) is very good disinfectant. But, presence of HCl will make difficulties to separate HOCl from HCl.