[clef]

Hi, i need some help with a titration problem.

Today I performed a titration using wine to determine the sulfur dioxide in the wine and titrating iodine into the sample:

SO₂+ 2H₂0(l) + I₂ = 3H⁺(aq) + HSO₄^-(aq) + 2I(aq)

We had to initially add sodium hydroxide to the sample of wine, then wait 15 minutes before adding sulfuric acid and titrating with iodine.

The question i am having trouble with is:

If the step which involved adding sodium hydroxide to the sample of wine and leaving it to stand were omitted, would the volume of iodine required in the titration be likely to be greater than, that same as, or less than the volume if the step is included in the procedure. Explain.

I have no idea how to go about working this out:(

[billnotgatez]

It is interesting that all the sites I looked at do not mention directly what happens to the sulfur dioxide when decanting. Indirectly they suggest that some is lost.

http://www.winecountrygetaways.com/decanting-wine.html
http://www.diwinetaste.com/dwt/en2006116.php
http://wineinsiders.com/wine/Wine-Trivia.cfm