Practical investigations
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I am doing an investigaion into the acidity of white wines. Could you tell me how to calculate the total acidity after pH titration with sodium hydroxide? One website said that 1 ml of sodium hydroxide solution = 1% total acidity, but surely the percentage depends on the concentration of sodium hydroxide solution used? If not, why did I have to standardize it? Please help!
Corrie writes ...
I would ignore what you have seen on the website - that obviously refers to a particular concentration of NaOH made up to to produce the 1 ml = 1% relationship.
You would be better just working out the moles of NaOH used in your titration from the volume and concentration you used.
The moles of hydroxide ions will be equal to the number of moles of H+ the alkali reacted with in the wine, both the free H+ and the H+ removed from the weak acids present - the 'total acidity'.
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updated: 17 April 2007
