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The ion MnOis often used to analyze for the Fe2+ content of an aqueous solution by using the (unbalanced) reaction Mno+Fe2+ + Fe3+ + Mn2+ in acidic solution. A 45.4 mL sample of a solution containing Fe2+ requires 63.3 mL of a 0.0330 M KMnO4 solution for complete reaction. What is the concentration of the Fe2+ in the original solution? A.) 0.0460 M B.) 0.230 M C.) 2.30 x 10-4 M D.) 4.60 x 10-5 M E.) 0.0920 M The molar mass of glucose = 180.2

Respuesta :

Answer:

B) 0.230 M

Explanation:

The first step is to balance the reaction between the Ferrous ion and the permanganate ion:

[tex]5~Fe^+^2~+~MnO_4^-^1~+~8H^+~->~5Fe^+^3~+~Mn^+^2~+4H_2O[/tex]

Then we have to calculate the moles of [tex]MnO_4^-[/tex]:

[tex]M~=~\frac{mol}{L}[/tex]

[tex]mol~=~M*L[/tex]

[tex]mol~=~0.033~M*0.0633L=~0.002088~mol~MnO_4^-[/tex]

Then using the molar ratio we can find the moles of [tex]Fe^+^2[/tex]:

[tex]0.002088~mol~MnO_4^-\frac{5~mol~Fe^+^2}{1~mol~MnO_4^-}=0.01044~mol~Fe^+^2[/tex]

Finally we can calculate the molarity:

[tex]M=\frac{0.01044~mol~Fe^+^2}{0.0455~L}=0.230~M[/tex]

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