Sciencemadness Discussion Board

Hydrogen Perozide and Chlorine

johnnygeneric - 7-12-2004 at 05:43

Hydrogen Peroxide is used to suck up dissolved Chlorine in water in the Chlor alkali business. What does it form??? Anyone know?

A possible solution...

cyclonite4 - 7-12-2004 at 06:24

Do you mean that they remove chloride ions from the water?

Hydrogen Peroxide reacts with chloride ions to produce free chlorine, water and oxide ions(water in the case of HCL) ... (heres the reaction)...

H2O2 + 2Cl- --> H2O + Cl2 + O2-

This may be it .... im not really sure based on ur description...

I am a fish - 7-12-2004 at 11:26

When chlorine dissolves in water, it exists as a mixture of hydrochloric and hypochlorous acids (except at low pH):

Cl<sub>2</sub> + H<sub>2</sub>O <--> HCl + HOCl

Hydrogen peroxide is capable of reducing hypochlorous acid into hydrochloric acid:

HOCl + H<sub>2</sub>O<sub>2</sub> -> HCl + H<sub>2</sub>O + O<sub>2</sub>

Therefore hydrogen peroxide can be used as a dechlorination agent, as its net effect is to convert chlorine into relatively inert hydrochloric acid:

Cl<sub>2</sub> + H<sub>2</sub>O<sub>2</sub> -> 2HCl + O<sub>2</sub>

I am a fish - 7-12-2004 at 11:39

Quote:
Originally posted by cyclonite4
Do you mean that they remove chloride ions from the water?

Hydrogen Peroxide reacts with chloride ions to produce free chlorine, water and oxide ions(water in the case of HCL) ... (heres the reaction)...

H2O2 + 2Cl- --> H2O + Cl2 + O2-

This may be it .... im not really sure based on ur description...

That certainly wouldn't happen.


Iodide and bromide ions are oxidised to the respective elements as follows:

2X<sup>-</sup> + H<sub>2</sub>O<sub>2</sub> -> X<sub>2</sub> + 2OH<sup>-</sup>

However, this reaction doesn't happen with chloride ions.


[Edited to fix subscript text]

[Edited on 8-12-2004 by I am a fish]

cyclonite4 - 8-12-2004 at 04:37

i stand corrected:D.... ive heard of these reactions with bromide and iodide... so i assumed it applied to all the halides :(