Oxidation Reaction: SO2 to H2SO4?

[gracy]

Is it right to say sulfur dioxide is oxidized to sulfuric acid? SO2 is converted into H2SO4, hydrogen is added so it should be reduction rather than oxidation.

 

[Borek]

I don't think I have ever heard about a method of producing sulfuric acid that uses hydrogen, can you elaborate?

 

[gracy]

I don't think I have ever heard about a method of producing sulfuric acid that uses hydrogen, can you elaborate?

I meant previously it was SO2(no hydrogen atom) and then it became H2SO4 (two hydrogen atoms)so it should be reduction why it is written in my textbook that SO2 is oxidised when it get converted into H2SO4?

 

[Bystander]

Formal oxidation states for oxygen are always -2. Minus eight for oxygen, plus two for two hydrogens, leaves plus six for sulfur. Compare that to plus four for sulfur in sulfur dioxide, and the sulfur has been further oxidized.

 

[Borek]

I meant previously it was SO2(no hydrogen atom) and then it became H2SO4 (two hydrogen atoms)so it should be reduction

Why do you ignore two added oxygen atoms?

 

[gracy]

Why do you ignore two added oxygen atoms?

Ok.So two hydrogen atoms and two oxygen atom ,so tie then why oxidation not reduction?

 

[gracy]

Formal oxidation states for oxygen are always -2. Minus eight for oxygen, plus two for two hydrogens, leaves plus six for sulfur. Compare that to plus four for sulfur in sulfur dioxide, and the sulfur has been further oxidized.

So we should say sulfur is oxidized rather than SO2 is oxidized.

 

[Bystander]

The starting state is sulfur dioxide, and it has been further oxidized.

 

[Borek]

Ok.So two hydrogen atoms and two oxygen atom ,so tie then why oxidation not reduction?

Why do you assume effect of a single oxygen atom is identical to effect of single hydrogen atom? Oxygen accepts two electrons, hydrogen donates one.

 

[gracy]

The starting state is sulfur dioxide, and it has been further oxidized.

OK I understood.