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A level Chemistry - redox question

Hi can someone explain this please?
3Cl2 + 2Fe -> 2FeCl3
The half equation to show reduction of chlorine is:
Cl2+ 2E- -> 2Cl-
Why is it reduced by 2E and why on the right side is it 2Cl-?
Have a feeling its quite simple but could someone explain please?
thx
Original post by danhas20
Hi can someone explain this please?
3Cl2 + 2Fe -> 2FeCl3
The half equation to show reduction of chlorine is:
Cl2+ 2E- -> 2Cl-
Why is it reduced by 2E and why on the right side is it 2Cl-?
Have a feeling its quite simple but could someone explain please?
thx

Chlorine turns into a negative ion essentially so it would have a 1- charge, except in fluorine where it would be 1+.
2 electrons is needed to reduce the Diatomic chlorine - 1 electron per chlorine.
And on the right side, it is 2Cl- because any atom that has a charge is never presented with a little number and because there were 2 chlorine atoms at the beginning, there's 2 chlorine ions at the end.

And from the initial equation you got up there which is 3Cl2 + 2Fe --> 2FeCL3
since each chlorine was reduced (1 electron to each chlorine), it would suggest that in 2FeCl3, the irons have 3+ charges. the electrons that reduced the chlorine were TRANSFERRED from the iron.

I hope this helps. I understand it is very confusing.
yeah, that is right.
FeCl3 is an ionic lattice, so splits up into Fe3+ and Cl-, so you have Cl2 --> Cl-. the electrons will go on the more positive side to balance the charges, hence 2e- + Cl2 --> 2Cl-.

this means that iron is oxidised: Fe --> Fe3+ + 3e-.
(then, if you put these two half equations together, you will get
3Cl2 + 2Fe -> 2FeCl3).
Original post by simxne_
yeah, that is right.
FeCl3 is an ionic lattice, so splits up into Fe3+ and Cl-, so you have Cl2 --> Cl-. the electrons will go on the more positive side to balance the charges, hence 2e- + Cl2 --> 2Cl-.

this means that iron is oxidised: Fe --> Fe3+ + 3e-.
(then, if you put these two half equations together, you will get
3Cl2 + 2Fe -> 2FeCl3).

You did it so much more simply than I did. I should ask for chemistry lessons from you.
Original post by JA03
Chlorine turns into a negative ion essentially so it would have a 1- charge, except in fluorine where it would be 1+.
2 electrons is needed to reduce the Diatomic chlorine - 1 electron per chlorine.
And on the right side, it is 2Cl- because any atom that has a charge is never presented with a little number and because there were 2 chlorine atoms at the beginning, there's 2 chlorine ions at the end.

And from the initial equation you got up there which is 3Cl2 + 2Fe --> 2FeCL3
since each chlorine was reduced (1 electron to each chlorine), it would suggest that in 2FeCl3, the irons have 3+ charges. the electrons that reduced the chlorine were TRANSFERRED from the iron.

I hope this helps. I understand it is very confusing.


Fluorine always forms compounds in the -1 oxidation state!!!

Other than that, brilliant answer.
Reply 5
Original post by JA03
Chlorine turns into a negative ion essentially so it would have a 1- charge, except in fluorine where it would be 1+.
2 electrons is needed to reduce the Diatomic chlorine - 1 electron per chlorine.
And on the right side, it is 2Cl- because any atom that has a charge is never presented with a little number and because there were 2 chlorine atoms at the beginning, there's 2 chlorine ions at the end.

And from the initial equation you got up there which is 3Cl2 + 2Fe --> 2FeCL3
since each chlorine was reduced (1 electron to each chlorine), it would suggest that in 2FeCl3, the irons have 3+ charges. the electrons that reduced the chlorine were TRANSFERRED from the iron.

I hope this helps. I understand it is very confusing.

thanks so much you legend
Reply 6
Original post by simxne_
yeah, that is right.
FeCl3 is an ionic lattice, so splits up into Fe3+ and Cl-, so you have Cl2 --> Cl-. the electrons will go on the more positive side to balance the charges, hence 2e- + Cl2 --> 2Cl-.

this means that iron is oxidised: Fe --> Fe3+ + 3e-.
(then, if you put these two half equations together, you will get
3Cl2 + 2Fe -> 2FeCl3).


thanks i never thought about it that way and have always struggled w half equations butt this makes sense so thanksss
Original post by TypicalNerd
Fluorine always forms compounds in the -1 oxidation state!!!

Other than that, brilliant answer.

I thought they were saying that chlorine would have an oxidation state of +1 when in a compound involving fluorine, ie ClF as fluorine is more electronegative, maybe?
Original post by simxne_
I thought they were saying that chlorine would have an oxidation state of +1 when in a compound involving fluorine, ie ClF as fluorine is more electronegative, maybe?


In that case, the statement is incomplete, as Cl also forms compounds in the +1 oxidation state with Oxygen.

Indeed I probably did misinterpret the initial post as I am functioning off of like 2 hours sleep lol

Edit: omfg I’m so tired I literally forgot to mention Chlorine actually forms compounds ranging from the +1 to +7 oxidation states. Take NaClO, ClO2, NaClO3 and NaClO4 as examples.
(edited 1 year ago)
Original post by TypicalNerd
In that case, the statement is incomplete, as Cl also forms compounds in the +1 oxidation state with Oxygen.

Indeed I probably did misinterpret the initial post as I am functioning off of like 2 hours sleep lol

Edit: omfg I’m so tired I literally forgot to mention Chlorine actually forms compounds ranging from the +1 to +7 oxidation states. Take NaClO, ClO2, NaClO3 and NaClO4 as examples.

oh yes, I forgot about the chlorate ion, sorry! I don't think it was completely clear, but it doesn't really matter anyway I guess
(edited 1 year ago)

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