Question

Using basic conditions, MnO4- can be used as titrant for the analysis of Mn2+, with both the analyte and the titrant ending up as MnO2. In the analysis of a mineral sample for manganese, a 0.5165-g sample is dissolved, and the manganese is reduced to Mn2+. The solution is made basic and titrated with 0.03358 M KMnO4, requiring 34.88 mL to reach the endpoint. Calculate the %w/w Mn in the mineral sample.

Answer 1

Titration step is
3Mn^2+ + 2MnO4^- + 4OH^- ==> 5MnO2 + 2H2O
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mols MnO4^- used = M x L = ?
mols Mn^2+ in the sample = mols MnO4^- x 3/2 = ?
grams Mn = mols Mn x atomic mass Mn = ?
%Mn = (grams Mn/mass sample)*100 = ?
Post your work if you get stuck.