[hydrowire]

allo everyone,

Consider this sentence:
In the presence of hydrogen ions, the hydroxyammonium ion, NH₃OH⁺ will reduce iron(III) ion to iron(II) ion while the NH₃OH⁺ ion itself will be oxidised to dinitrogen oxide.

I wrote a formula equation regarding to the above sentence:
4 Fe³⁺ + 2 NH₃OH⁺ --> 4 Fe²⁺ + N₂O + H₂O + 6H⁺

But my chemistry teacher suggested that the hydrogen ions in my equation should be the reactants(infront of the equation) not the product. So she wrote:
Fe³⁺ + 2 NH₃OH⁺  + 2H⁺ + 5e^- --> Fe²⁺ + N₂O + H₂O + 4 H₂

But I'm totally disagreed with her because as I know(might be wrong) that redox equations should not have e^- (electron charge) present right? It should be cancle off in the redox equation.
Although I disagreed with her equation, I agree of what she said about the hydrogen ions. Yes it should be infront of the equation because it is a acid solution and according to the sentence "with the presence of hydrogen ions".

Anyone have any idea on this redox problem? Or maybe a better and correct equation for this?

BTW, the NH₃OH⁺ ion came from a solution prepared by boiling 4.0 g of hydroxyammonium sulphate, (NH₃OH)₂SO₄ per dm³  with excess iron(III) ammonium sulphate and dilute sulphuric acid.
Later this solution was titre with a solution containing 1.58 g of potassium manganate(VII) KMnO₄ per 500 cm³ to determine the ratio of the number of moles of hydroxyammonium ions to the number of moles of iron(III) ions participating in the reaction.

Hope I made myself clear.
Thx in advance!

[Borek]

But I'm totally disagreed with her because as I know(might be wrong) that redox equations should not have e^- (electron charge) present right? It should be cancle off in the redox equation.

No idea what is wrong here (and no time to investigate at the moment), but you are right - full balanced redox equation doesn't show electrons coming from nowhere. If the electrons are visible it is half-reaction, which is not the case.

[sdekivit]

allo everyone,

Consider this sentence:
In the presence of hydrogen ions, the hydroxyammonium ion, NH₃OH⁺ will reduce iron(III) ion to iron(II) ion while the NH₃OH⁺ ion itself will be oxidised to dinitrogen oxide.

your reaction is correct.

[hydrowire]

your reaction is correct.

But shouldn't the hydrogen ions be infront of the equation?
Do you mine to give some explanation of why I'm correct?

[sdekivit]

2 NH3OH(+) --> N2O

2 NH3OH(+) --> N2O + H2O

2 NH3OH(+) --> N2O + H2O + 6 H(+)

2 NH3OH(+) --> N2O + H2O + 6 H(+) + 4 e-

then combined with 4 Fe(3+) + 4 e- --> 4 Fe(2+) will result in your reaction equation.

Maybe the H(+) is a catalist in the reaction.

[Borek]

But shouldn't the hydrogen ions be infront of the equation?
Do you mine to give some explanation of why I'm correct?

You are not told they take part in the reaction - they are needed.

[Yggdrasil]

An interesting side-note:

A reaction like the one described by the teacher could possibly take place in a solution of liquid ammonia as free electrons are solvated by ammonia.  Of course, this is beyond the scope of a high school course and you would not be expected to know this.

[hydrowire]

sdekivit: Maybe the H(+) is a catalist in the reaction.

Where does the H⁺ ion came from? Is it from the dilute sulphuric acid that added previously?

Borek: You are not told they take part in the reaction - they are needed.

Needed as a catalyst?

[Mitch]

Any acid will be said to yield H⁺ in solution

[hydrowire]

Any acid will be said to yield H+ in solution

I know. My problem is whether the H⁺ ion should be involved in the equation.

[Borek]

Where does the H⁺ ion came from? Is it from the dilute sulphuric acid that added previously?

Yes. Every acid solution contains them.

Needed as a catalyst?

As sdekivit suggested.

[AWK]

There is no need to use H2SO4 in the first reaction - solution containing Fe2(SO4)3 and (NH3OH)2SO4 is acidic itself because of hydrolysis of both reagents. Moreover, the sulfuric acid is produced in this reaction, but slightly more of  sulfuric acid is needed in the next step of oxidation.

2Fe2(SO4)3 + (NH3OH)2SO4 = 4FeSO4 + N2O + H2O + 3H2SO4

4FeSO4 + 3H2SO4 + 0.8KMnO4 + 0.2H2SO4 = 2Fe2(SO4)3 + 0.4K2SO4 + 0.8MnSO4 + 3.2H2O

[hydrowire]

2Fe2(SO4)3 + (NH3OH)2SO4 = 4FeSO4 + N2O + H2O + 3H2SO4

what with the Fe2(SO4)3? the soulution is mixed with iron(III)ammonium sulphate, where is the ammonium?

There is no need to use H2SO4 in the first reaction

maybe as a catalyst?

[AWK]

quotes from last post of hydrowire

what with the Fe2(SO4)3? the soulution is mixed with iron(III)ammonium sulphate, where is the ammonium?

Read carefully
quote from the first post of hydrowire

In the presence of hydrogen ions, the hydroxyammonium ion, NH3OH+ will reduce iron(III) ion to iron(II) ion while the NH3OH+ ion itself will be oxidised to dinitrogen oxide.

maybe as a catalyst?

Acid is added to ensure a proper stoichiometry in the oxidation of FeSO4 by permanganate[/color]

[seong8737]

Im sorry if Im asking a dumb question.
But isnt Fe(3+) + 2NH3OH(+) --> Fe(2+) + N2O + H20 + 6H have balanced the equation already? Why do we still need to add 2 infront of Fe(3+0 and Fe(2+)?

I know I must be wrong. Can someone please correct me?^_^