Chem 200 Lab Report
Experiment 6 : Redox titration
Course Instructor: Dr Lisa Diab
Student Name: Marwa Noaman
To determine a substance analytically, oxidation- reduction reactions are used.
During any redox reaction transferring of reactions occurs from a reducing agent to an oxidizing agent. Purpose:
* To titrate "Mohr's salt" solution with KMNO4,(second standard) which has to be standardize with oxalic acid (first standard). * To learn how acid-base reactions could be used in titration analyses of unknown substances with basic components. * To standardize potassium permanganate solution KMNO4, which then be used for titration of iron unknown solution. * To write the net ionic equations of redox reaction carried out in this experiment. * Concept of experiments:
* A standard KMNO4 solution, used in this experiment as titrant, cannot be prepared directly by dissolving of a known amount of solid KMNO4 because this reagent is a very strong oxidizing agent. Solutions of potassium permanganate are unstable and their concentration changes slowly from time to time. * In this experiment a standard solution of 0.1 N oxalic acid is used for the standardization KMNO4, potassium permanganate oxidizes oxalic acid (C3+) to carbon dioxide (C4-) and water while itself being reduced to Mn2+.
Chemicals, Glassware, Equipment Required:
Chemicals: Potassium permanganate, ferrous ammonium sulfate (Mohr's salt), 1M sulfuric acid, and 0.1N oxalic acid solution. Glassware: 50ml burette, 250ml Erlenmeyer flask , 10ml graduated pipette ,100 and 250ml beakers, graduated cylinder, funnel. Equipment: ring stand with a clamp for burette, Bunsen burner, safety glasses, marking pen. Procedure:
it is the same as manual.
A) Standardization of a KMNO4 solution by titrating it against an oxalic acid solution: Data and calculation:
Mass of oxalic acid acid=1.5068
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