Question 3: Redox Titration (11 points)

Use the image below to answer the following questions about redox titrations.

The image is two beakers, the left with clear liquid and the right with purple liquid with Fe[sup]2+ in the middle with an arrow pointing to the right beaker.

a. Write 2–3 sentences describing and identifying the type of chemical reaction that occurs when Fe2+ reacts with potassium permanganate (KMnO4) and specifying the type of solution required for the reaction to occur. (2 points)

b. Using a standard reduction potential table, identify the oxidation and reduction half-reactions for the reaction. (4 points)

c. Write the balanced net ionic equation for the reaction, and identify which substance is oxidized and which is reduced. (3 points)

d. Suppose at the endpoint of the reaction 0.030 moles of KMnO4 were added to the analyte. How many moles of Fe2+ were contained in the beaker? (2 points)

1 Answer

  • 1 month ago
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    Ferrous ion is oxidized:

    Fe2+→Fe3++e− (i)

    And permanganate ion is reduced:

    we have a redox reaction 

    MnO−4+8H++5e−→Mn2++4H2O(l) (ii)

    after addition and cancellation....


    This is balanced with respect to mass and charge.

    The colour change of the reaction, deep-purple permanganate to almost colourless Mn2+, would give us a visual gauge on the extent of reaction.

    If 0.030moles of MnO4- were added we will have 0.030 * 5 moles of Fe2+ at the equivalence point in the beaker 

    =0.15 moles  

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