OCR A2 Planning Exercise - Help ~~~~~~~~~ Watch

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Yilin510
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If anyone here know the reason of adding H2SO4 into the solution of MnO4- and Fe2+, i.e. why it is neccessary to make the solution acidic ? :confused:

And if then, why don't use HCl or other acids to make it acidic? :dontknow:

Also as the plan given, it says to determine the concentration of the aqueous chlorine solution, but lots of calculations is according to the approx. concentration it is given as 7g dm-3, so how to finish the calculations in the plan I mean as the approx. amount of chlorine we used is 0.1mol, in this case how to finish the assessment, if I need to come over again to calculate the original concentration used for chlorine solution :rolleyes:

Cheers :p:
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charco
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MnO4- needs H+ ions for its reduction to Mn2+ by the equation:

MnO4- + 8H+ + 5e ---> Mn2+ + 4H2O

you cant use HCl to provide the H+ because the manganate VII ion will oxidise the chloride ions to chlorine gas in the presence of H+ ions
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Borek
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(Original post by Yilin510)
[FONT=Comic Sans MS][COLOR=Red]If anyone here know the reason of adding H2SO4 into the solution of MnO4- and Fe2+, i.e. why it is neccessary to make the solution acidic ?
Additionally Fe3+ that forms requires slightly acidic solution to not precipitate as hydroxide.

Best,
Borek
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