Chemistry 2e · 17.1 Review of Redox Chemistry

Review of Redox Chemistry: practice problems

5 problems from the book, with its answers. Check your working, or have any of them explained to you on the whiteboard.

1. Exercises 1

   Identify each half-reaction below as either oxidation or reduction.

   (a) ${\text{Fe}}^{3+}+{\text{3e}}^{\text{-}}⟶\text{Fe}$

   (b) $\text{Cr}⟶{\text{Cr}}^{3+}+{\text{3e}}^{\text{-}}$

   (c) ${\text{MnO}}_4{}^{2-}⟶{\text{MnO}}_4{}^{-}+{\text{e}}^{\text{-}}$

   (d) ${\text{Li}}^{\text{+}}+{\text{e}}^{\text{-}}⟶\text{Li}$

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2. Exercises 3

   Assuming each pair of half-reactions below takes place in an acidic solution, write a balanced equation for the overall reaction.

   (a) $\text{Ca}⟶{\text{Ca}}^{2+}+{\text{2e}}^{\text{-}},$ ${\text{F}}_2+{\text{2e}}^{\text{-}}⟶{\text{2F}}^{\text{-}}$

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3. Exercises 5

   Identify the oxidant and reductant of each reaction of the previous exercise.

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4. Exercises 7

   Identify the oxidant and reductant of each reaction of the previous exercise.

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5. Exercises 9

   Why don’t hydrogen ions appear in equations for half-reactions occurring in basic solution?

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