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Transition metal help please

When dissolved in dilute sulfuric acid, the number of moles of ethanedioate ions in a pigment can be determined by titration with acidified potassium manganate(VII).
Explain why the titration of a sample of iron(II) ethanedioate would require a different amount of potassium manganate(VII) than a titration of an equimolar amount of copper(II) ethanedioate.
Reply 1
Avatar for Pigster
Pigster
20
Original post by anactualmess
When dissolved in dilute sulfuric acid, the number of moles of ethanedioate ions in a pigment can be determined by titration with acidified potassium manganate(VII).
Explain why the titration of a sample of iron(II) ethanedioate would require a different amount of potassium manganate(VII) than a titration of an equimolar amount of copper(II) ethanedioate.

Why do you think it might be?

What is different about the two solutions?
different oxidation states?
Original post by Pigster
Why do you think it might be?

What is different about the two solutions?
I am still very confused lol
Original post by Pigster
Why do you think it might be?

What is different about the two solutions?
Original post by anactualmess
I am still very confused lol


Both iron and ethandioate ions react with the oxidising agent
sorry I still don't really understand
Original post by charco
Both iron and ethandioate ions react with the oxidising agent
Reply 6
Avatar for Dilof
Dilof
11
Original post by anactualmess
sorry I still don't really understand

Fe2+ and C2O4 2- both react with the MnO4- ions whereas the copper ions do not, thats the difference.

5Fe2+ + MnO4- + 8H+ > 5Fe3+ + Mn2+ + 4H2O
5C2O4(2-) + 2MnO4- + 16H+ > 8H2O + 2Mn2+ + 10CO2
(edited 4 years ago)
thank you! So would a greater volume of potassium manganate be needed for iron ethanedioate?
Original post by Dilof
Fe2+ and C2O4 2- both react with the MnO4- ions whereas the copper ions do not, thats the difference.
Reply 8
Avatar for Dilof
Dilof
11
Original post by anactualmess
thank you! So would a greater volume of potassium manganate be needed for iron ethanedioate?


Yes
thanks, one more question, how would I know that copper ions don't react with MnO4- ions?
Original post by Dilof
Yes
Original post by anactualmess
thanks, one more question, how would I know that copper ions don't react with MnO4- ions?


copper has no higher oxidation state than 2+
Original post by charco
copper has no higher oxidation state than 2+


ah okay thank you

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