[sinthreck]

Ammonium metavanadate reacts with sulfur dioxide in acidic solution as follows (H⁺ ions and H₂O were omitted from this equation):
x VO^3- + y SO₂  →  x VO₂+ + y SO₄^2-
The ratio x : y (Enter both stoichiometric coefficients)

I have 3 possible answers:
1) 2:1 (Answer Key)
2) 1:1 (People on yahoo answers - The question was asked over a year ago)
3) 2:3 (My calculated value)

My calculation:

SO₂  + 2e^-   SO₄^2-   x 3
VO₃^- VO²⁺ +3e^-  x 2

This equals:

3SO₂  + 6e^-   3SO₄^2-   
2VO₃^- 2VO²⁺ +6e^- 

Electrons cancel and you have:

2VO₃^- + 3SO₂    2VO²⁺ + 3SO₄^2-

This is a ratio of 2:3

Please *delete me*

[sjb]

VO^3-, or VO₃^-? The two are different beasts. One has 2 atoms, the other 4. Having said that, I can't see both VO^3- and SO₂ gaining oxygen unless you've missed out something - perhaps the acid is also involved in the reaction equation?

[sinthreck]

Hi, You're correct. I made a typo when stating the question. Unfortunately, I don't think I can edit my original post

The question should state the equation as follows:

x VO₃^- + y SO₂  →  x VO²⁺ + y SO₄^2-

My calculations were correct (at least no typos).

[sinthreck]

Actually, I have changed my answer now and I agree with the answer key

I added in the H+ and H2O and got the correct result.