Question

Question 3: Redox Titration (11 points)

Answer 1

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

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 30 moles of KMnO4 were added to the analyte. How many moles of Fe2+ were contained in the beaker? (2 points)

Answer 2

@Hoslos Let's start with b)

Answer 3

Acording to their potentials,Fe2+ is positive and Mno4 is also positive, meaning one of the potentials has to made negative, to promote attractive and eventual reaction. We can make the manganate as negative, because after all it is an anion.
Hence +0.77 - 0.56 = + 0.21.

Answer 4

thanks. ok now c)

Answer 5

Fe2+ + MnO4^-1 - Fe + MnO4^-2. I believe this is the answer.

Answer 6

thanks! :) now d)

Answer 7

According to their potentials, MnO4- loses 1 electron, whereas Fe2+ adds 2 electron, meaning they are in the ratio of 1:2, respectively. Hence, if you have 30 of MnO4-, then you have 30*2=60 mol of Fe.