[pcm81]

So, i've made a mistake of looking up articles about titration of iron with KMnO4 as the result of other iron thread. In those articles i see use of zinc or tin chloride to make sure that all iron is in +2 state. Which makes sense.
The specific case that i am interested in is titration for iron content in phosphating bath, which is a solution of iron phosphate, Mn phosphate, phosphoric acid, sodium nitrate and water at pH 2.75 ish. The tutorial i saw on youtube skips the zinc or tin chloride step and goes straight for addition of 1ml of 50% H2SO4 followed by 0.18N KMnO4 titration.

My question is:
Is skipping the step of oxidising Fe3+ to Fe2+ a mistake and actually needs to be done in this situation OR is all iron going to be in Fe2+ state due to the chemistry of this particular mixture?

Thanks ahead

[chenbeier]

Probably they only want to know the Fe²⁺ not the Fe³⁺ content.
To get total iron a reduction is a must.