Hydrogen peroxide titration help Watch

OwenJenkins12
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I want to do a titration to work out the rate of decomposition of hydrogen peroxide

I know that ou can do this by taking samples of the reaction mixture at different times and running them into an acidified solution of potassium iodide. The iodine produced can be titrated with a solution of thiosulphate using starch indicator:

2H+ + H2O2 + 2I– → I2 + 2H2O

I2 + 2S2O32– → 2I– + S4O6 2–

The volume of thiosulphate solution required for the titration provides a measure of the amount of hydrogen peroxide in the reaction mixture at the different times. I aslo know that my concentration of Hydrogen peroxide is approx 0.5moles.

So my questions are:
what volume of hydrogen peroxide would I need?
What volume and concentration of potssium iodide would i need?
What volume and concentration of sodium thiosluphate would i need?

Thank-you!
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Borek
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When it comes to concentrations, consult http://www.titrations.info/iodometri...tion-solutions

From these you should be able to evaluate hydrogen peroxide volume required (same site has a discussion of the titrant and sample volume).

When it comes to hydrogen peroxide I prefer titration with permanganate.
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addylad
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(Original post by OwenJenkins12)
I want to do a titration to work out the rate of decomposition of hydrogen peroxide

I know that ou can do this by taking samples of the reaction mixture at different times and running them into an acidified solution of potassium iodide. The iodine produced can be titrated with a solution of thiosulphate usingstarch indicator:

2H+ + H2O2 + 2I– → I2 + 2H2O

I2 + 2S2O32– → 2I– + S4O6 2–

The volume of thiosulphate solution required for the titration provides a measure of the amount of hydrogen peroxide in the reaction mixture at the different times. I aslo know that my concentration of Hydrogen peroxide is approx 0.5moles.

So my questions are:
what volume of hydrogen peroxide would I need?
What volume and concentration of potssium iodide would i need?
What volume and concentration of sodium thiosluphate would i need?

Thank-you!
You are getting there. Your iodide will be in excess. The thiosulphate concentration will depend on the peroxide concentration which you know. You can play around with the conc. of thiosulphate to get a large enough titre. Bearing in mind the peroxide will decompose, your titre will obviously decrease.

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