In Part IIA, a student uses 0.020061 M KMnO4 to titrate a sample containing oxal

Question

In Part IIA, a student uses 0.020061 M KMnO4 to titrate a sample containing oxalate ions, C2O42-:

5 C2O42-+ 2 MnO4-+ 16H+ 10 CO2 + 2 Mn2+ + 8 H2O

These data were obtained:
- Initial buret reading: 1.38 mL KMnO4 solution
- Final buret reading: 14.78mL KMnO4 solution

A) Show a complete calculation of how you determine the number of moles of C2O42- ions that reacted with the MnO4- in the KMnO4 solution.

B) What would happen if,
- KMnO4 is added too rapidly?
- Oxalate solution is not swirled sufficiently?
- Oxalate solution is not hot enough?

C) What is the purpose of the experiment?

D) Write the name and formula of all the chemicals used in this experiment.

PART II: ANALYSIS OF A COMPLEX SALT In the remainder of this experiment, you will determine the percentage composition of two components of the complex salt, iron and oxalate, to assist you in obtaining the simplest formula of your salt. The salt is known to be a trihydrate (that means it contains three water molecules per simplest formula). The amount of iron and oxalate ions in a known amount of the salt will be determined using the volumetric procedure described below. Then the amount of potassium can be determined using the known charges of the ions and the necessary stoichiometric relationships between cations and anions in neutral salts The determinations of oxalate and iron involve redox titrations. In both cases, the titrant is a known-concentration solution of potassium permanganate (KMn04). A standardized solution of potassium permanganate solution will be provided to you PART IIA: OXALATE ANALYSIS Volumetric Redox Analysis of Oxalate Using Potassium Permanganate plex salt dissociates it into separate potassium ions, iron(lII) ions, oxalate ions, and water molecules. Because iron and potassium are already in their most oxidized forms (Fe3+ and K+), you don't need to worry about KMn04 oxidizing them

Explanation / Answer

For the given experiment

A) Molarity of KMnO4 solution = 0.020061 M

Volume of KMnO4 used = (final - initial)volume = 13.4 ml

moles KMnO4 used = 0.020061 M x 13.4 ml = 0.27 mmol

2 moles MnO4- reacts with 5 moles C2O4^2-

so,

moles C2O4^2- reacted = 0.27 mmol x 5/2 = 0.675 mmol

B) what would happen if,

-KMnO4 added too rapidly : the end point of tiration would pass and exceed by addition of more of KMnO4. higher moles of C2O4^2- would be calculated in this case.

-Oxalate solution is not swirled : The solution won't mix and incorrect early end point would be noticed. Lower moles of C2O4^2- would be calculated in this case.

-Oxalate solution is not hot enough : slower rate of reaction, end point would be reached early, lower moles of C2O4^2- obtained.

C) Purpose of expeirment is to determine molariy of unknown oxalate solution by titration with KMnO4.

D) name and formula of compound used in experiment

Na2C2O4 : sodium oxalate

KMnO4 : potassium permanganate

H2SO4 : sulfuric acid

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