Inorganic Chemistry Question

[ProfessorB]

A student was told that vanadium (V) can be reduced by SO2. He decided to investigate this by the following procedure:
2.23g of ammonium vanadate was dissolved in dilute sulphuric acid and made
up to 250cm3. Sulphur dioxide gas was bubbled through the solution until there
was no further colour change. The solution was then boiled for 5 minutes and
allowed to cool. A 25cm3 aliquot of this was then titrated against 0.02M KMnO4
solution and required 38.1cm3 to oxidise the vanadium solution back to the (V)
oxidation state.
From this information determine the oxidation state of the reduced vanadium solution.

[theprof]

I won't provide the answer here as I consider that you really need to go through the calculations yourself. This is not a particularly difficult titration question and you need to return to your lecture notes or textbooks to arrive at the answer.

[ProfessorB]

Thanks for your time in 'answering' my question! This is not for me but is on behalf of niece. It is 40+ years since I did this stuff myself. If you can help further, thank you, if not it's back to Google for me!

[factor-fiction]

If you ask her to look at her notes and come up with an attempted answer for you or her to post on here, someone may be able to fill in the gaps

[theprof]

Yes, I think that if your niece outlines how far she understands the question and the calculations, we can help her further. AB is not really conducive to display lengthy calculations to answer the question in full, so by all means, let us see how far she has got.

[ProfessorB]

Thanks all. I worked it out for myself in the end and discussed it with her by Skype!
All's well that ends well!!!