Question

Post-Lab Questions: 1. Why must the permanganate solution be boiled and filtered before titrating? How does the absence of this step affect the results? 2. What happens if not enough acid was added to the iron solution before the titration was started? 18

Answer 1

1.Potassium permanganate solutions are boiled before titration to destroy the reducible substances such as traces of organics,chemicals and minerals remaining in de ionized water like calcium ,chlorides and magnessium etc.

After cooling the solution is filtered through a glass filtering crucible to remove manganese dioxide precipitates.Potassium permanganate solutions are unstable and filtered after a long storage to remove the impurities formed by manganese dioxide.

It is difficult to achieve an accurate ,correct titration result if boiling and filtration process missed before titration.

2. Titartion is a process to determine the concentration of a solution by adding known amount of another chemical changes until colour changes occur.potassium permangante is used for titration process.

So, it is necessary to standardize potassium permanganate solution by adding acid into it to know the exact concentration of the solution.

If standardised KMnO4 solution used, this will help to get a clear,transparent and reliable titration result in the end.Accurate titration result will be obtained when the exact concentration of the volumetric solution is known.