Practice Oxidation in Chemistry

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

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Quick Recap

The loss of electrons by an atom, ion, or molecule during a chemical reaction, resulting in an increase in its oxidation state.

Giving away electrons. Originally meant 'gaining oxygen' but it's broader.

Showing a random 20 of 50 problems.

Example 1

hard
Combine Mg→Mg2++2e−\text{Mg} \rightarrow \text{Mg}^{2+} + 2e^- and Al3++3e−→Al\text{Al}^{3+} + 3e^- \rightarrow \text{Al} into a balanced overall equation.

Example 2

medium
In Cl2+2Br−→2Cl−+Br2\text{Cl}_2+2\text{Br}^-\rightarrow2\text{Cl}^-+\text{Br}_2, which species is oxidized?

Example 3

challenge
In MnO4−→Mn2+\text{MnO}_4^-\rightarrow\text{Mn}^{2+}, Mn changes oxidation state. Determine whether Mn is oxidized or reduced and the electrons involved.

Example 4

easy
The species that gets oxidized acts as the oxidizing agent or the reducing agent?

Example 5

easy
At which electrode does oxidation occur in an electrochemical cell?

Example 6

medium
Show how a galvanic cell with Zn anode and Cu cathode uses oxidation.

Example 7

medium
In 2Mg+O2→2MgO2\text{Mg}+\text{O}_2\rightarrow2\text{MgO}, write Mg's oxidation half-reaction.

Example 8

hard
Balance the oxidation of I−\text{I}^- to IO3−\text{IO}_3^- in acidic solution.

Example 9

easy
In Zn→Zn2++2e−\text{Zn}\rightarrow\text{Zn}^{2+}+2e^-, is zinc oxidized or reduced?

Example 10

easy
Is iron rusting an example of oxidation? Explain.

Example 11

medium
Which is the stronger reducing agent under standard conditions, Zn or Cu? Why?

Example 12

medium
In the reaction CuO+H2→Cu+H2O\text{CuO} + \text{H}_2 \rightarrow \text{Cu} + \text{H}_2\text{O}, which substance is oxidized?

Example 13

easy
True or false: oxidation must always involve oxygen gas.

Example 14

medium
Carbon in CH4\text{CH}_4 (−4-4) becomes CO2\text{CO}_2 (+4+4). How many electrons does each carbon lose?

Example 15

challenge
Balance the oxidation of ethanol to acetic acid in acidic solution: C2H5OH→CH3COOH\text{C}_2\text{H}_5\text{OH} \rightarrow \text{CH}_3\text{COOH}.

Example 16

medium
Is the bleaching of a stain by hydrogen peroxide a kind of oxidation?

Example 17

medium
In 2H2S+O2→2S+2H2O2\text{H}_2\text{S} + \text{O}_2 \rightarrow 2\text{S} + 2\text{H}_2\text{O}, which atoms are oxidized?

Example 18

medium
Why is burning hydrogen (2H2+O2→2H2O2\text{H}_2+\text{O}_2\rightarrow2\text{H}_2\text{O}) an oxidation of hydrogen?

Example 19

medium
In Fe+CuSO4→FeSO4+Cu\text{Fe} + \text{CuSO}_4 \rightarrow \text{FeSO}_4 + \text{Cu}, write the oxidation half-reaction.

Example 20

medium
Cu→Cu2++2e−\text{Cu} \rightarrow \text{Cu}^{2+} + 2e^- has E∘=−0.34E^\circ = -0.34 V. What does the negative value mean for spontaneity as written?
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