When iron(II) sulphate solution is mixed with dilute sulphuric acid and a small amount of an orange solution, chemical reaction occurs and the oxidation number of iron changes from +2 to +3
a) suggest what the orange solution might be.
b) what would be observed in this reaction?
c) Explain whether iron(II) sulhate solution acts as a R.A.or an O.A. in this reaction.
D) Write a redox equation for the reacton involved.
chemistry question(R.A.&O.A.)
2009-03-18 1:20 am
回答 (3)
2009-03-18 3:53 am
✔ 最佳答案
a)The orange solution might be potassium dichromate solution (or sodium dichromate solution).
b)
The pale green iron(II) sulphate solution changes to yellowish brown, and the orange potassium dichromate solution changes to green. Therefore, the final solution is yellowish green in colour.
c)
Iron(II) sulphate solution acts as a reducing agent. This is because it is used to reduce the dichromate ion (O.N. of Cr = +6) to chromium(III) ion (O.N. of Cr = +3), while the iron(II) ion (O.N. of Fe = +2) itself is oxidized to iron(III) ion (O.N. of Fe = +3).
d)
6Fe2+(aq) + Cr2O72-(aq) + 14H+(aq) → 6Fe3+(aq) + 2Cr3+(aq) + 7H2O(l)
=
2009-03-20 2:33 am
This orange solution is Dichromate (Cr2O7 ^2-) solution.
Cation can be K+ , Na+...
It reduces inself and acts as an oxidizing agent to oxidize Iron(II) to
Iron(III).
Cr2O7 ^2- will reduce to GREEN Chromate(III).
Therefore, Iron(II)sulphate is reducing agent.
Equations:
Half equation:
Fe2+ <-----> Fe3+ + e-
Cr2O7 ^2- + 6e- + 14H+ <-----> 2Cr3+ + 7H2O
Overall: 6Fe2+ +Cr2O7 ^2- + 14H+ <----> 6Fe3+ + 2Cr3+ + 7H2O
Cation can be K+ , Na+...
It reduces inself and acts as an oxidizing agent to oxidize Iron(II) to
Iron(III).
Cr2O7 ^2- will reduce to GREEN Chromate(III).
Therefore, Iron(II)sulphate is reducing agent.
Equations:
Half equation:
Fe2+ <-----> Fe3+ + e-
Cr2O7 ^2- + 6e- + 14H+ <-----> 2Cr3+ + 7H2O
Overall: 6Fe2+ +Cr2O7 ^2- + 14H+ <----> 6Fe3+ + 2Cr3+ + 7H2O
2009-03-19 2:53 am
The orange solution is sodium dichromate solutio
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