You are right that it wouldn't work though. Precipitating iron with base gives a whole mess of hydrous hydroxide/oxide, and there's no way of knowing
how many moles were precipitated, since it wouldn't even be clear how many moles of base would need to be added to affect precipitation. Iodometry is
a good method. All you need is KI, starch indicator, and a standard thiosulfate solution. You would need to standardize the thiosulfate solution prior
to titrating the unknown using a solution containing a known amount of Fe(III). |