Please Explain this reation to me.. Very Briefly

[Maisara-WD]

Hi All

Will you please please explain this reaction to me.. Very Briefly??

The reaction of a metal eg. Fe with an oxidizing acid eg. conc sulphuric or dil or conc nitric...

Fe + 4HNO3 -----> Fe(NO3)3 + 2H2O + NO

3Fe + 8H2SO4 ----conc hot-----> Fe(SO4)3 + 4SO2 + 8H2O

Of course passivation occurs with conc Nitric acid.

I need your help to get the whole staff in my mind... I have millions of undescribable questions.. explain and help me please ;)

thanx very very much

[morrobay]

Hi All

Will you please please explain this reaction to me.. Very Briefly??

The reaction of a metal eg. Fe with an oxidizing acid eg. conc sulphuric or dil or conc nitric...

Fe + 4HNO3 -----> Fe(NO3)3 + 2H2O + NO

3Fe + 8H2SO4 ----conc hot-----> Fe(SO4)3 + 4SO2 + 8H2O

Of course passivation occurs with conc Nitric acid.

I need your help to get the whole staff in my mind... I have millions of undescribable estions.. explain and help me please ;)

thanx very very much
Im altering your original reactions for the following explanation
2Fe + 4(HNO3) ---> 2(Fe(NO3)2) + 2H2

2Fe + 4(H2SO4) ---> 2(FeSO4) + 2(SO2) + 4(H2O)

Reactions are driven by thermodynamics and/or by entropy
In the first reaction the nitrate group is preferentially oxidizing the iron and releasing hydrogen. The hydrogen is displaced here since the heat of formation,( the enthalpy change),of iron nitrate is greater than the heat of formation of nitric acid. So the products are in lower energy than the reactants.
For the second reaction Ill just say that the above also applies to the sulphate group ,in terms of preferentially oxidizing the iron with a greater delta H
And there is also an increase in entropy

[Borek]

Will you please please explain this reaction to me.. Very Briefly??

Please elaborate - explain what?

Please note that at least iron(III) sulfate formula is wrong. Can be a typo.

2Fe + 4(HNO3) ---> 2(Fe(NO3)2) + 2H2

2Fe + 4(H2SO4) ---> 2(FeSO4) + 2(SO2) + 4(H2O)

Both reactions are wrong.

First - no need for some of the parentheses, it is not 4(HNO3) but 4HNO3.

Second - nitric acid is a strong oxidizer, so it will produce Fe(III), not Fe(II). That means also reducing nitric acid to its oxides.

Third - in the reaction with sulfuric acid, if you put SO2 between products, that means you are assuming sulfuric acid acted as an oxidizer. That means iron is oxidized further than to +2, to oxidize it to +2 just H+ is enough.

[morrobay]

For the first reaction if it was dilute nitric acid and iron then the iron could be Fe ++,
2Fe + 4HNO3 ---> 2Fe(NO3)2 +2H2
For the second reaction with iron and sulfuric acid I would have originally put:
Fe + H2SO4 ---> FeSO4 + H2

correct?

[Borek]

Much better now.

[lightarrow]

Can't understand how you write hydrogen as a product in the reaction metal + HNO3: hydrogen reduces immediately NO3- in those conditions.

The correct one is the first written by the OP:

Fe + 4HNO3 -----> Fe(NO3)3 + 2H2O + NO

Furthermore, if HNO3 is very diluted, hydrogen reduces NO3- even to ammonium ion...

[Maisara-WD]

Second - nitric acid is a strong oxidizer, so it will produce Fe(III), not Fe(II). That means also reducing nitric acid to its oxides.


That's what I do want to understand...

WHY and how the strong oxidizers as conc sulphuric acid or nitric acid produce Fe(III) and not Fe(II)...
And more important: What is the basis on which these oxidizers are reduced into their oxides>>??

thank u all guys..

I'm waiting

[Borek]

WHY and how the strong oxidizers as conc sulphuric acid or nitric acid produce Fe(III) and not Fe(II).

It is all in th eredox potentials.

What is the basis on which these oxidizers are reduced into their oxides>>??

No idea what you are asking about. That's the way the react when they act as oxidizers.

[morrobay]

Can't understand how you write hydrogen as a product in the reaction metal + HNO3: hydrogen reduces immediately NO3- in those conditions.

The correct one is the first written by the OP:

Fe + 4HNO3 -----> Fe(NO3)3 + 2H2O + NO

Furthermore, if HNO3 is very diluted, hydrogen reduces NO3- even to ammonium ion...

OK
Your right. It looks like i took a wrong turn on this.
Not having my 1A, 1B text doesnt help.