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Topic 11: Redox and electrochemistry

12. Half-reaction: Describing changes in half-reaction equations

1. Given the half reaction equation below
3+
-
3+ Fe + 3e ---- Fe
Fe is
1) Reduced by gaining 3 electrons 3) Oxidized by gaining 3 electrons
4) Oxidized by losing 3 electrons

2) Reduced by losing 3 electrons

2. Given the half-reaction equation below - 2+
4+
4+ Sn + 2e ----- Sn
Sn is
1) Oxidized by gaining 2 electrons 3) Reduced by gaining 2 electrons
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2) Oxidized by losing 2 electrons 4) reduced by losing 2 electrons

3. In the half-reaction equation below: 2+ -
Ca ------------ Ca + 2e
Which is true of calcium atom?
1) It is oxidized by gaining 2 electrons 3) It is reduced by gaining 2 electrons
2) It is oxidized by losing 2 electrons
4) It is reduced by losing 2 electrons

4. In the half-reaction equation below - 3-

P + 3e ------- P
The phosphorous atom is
1) Oxidized, and becomes the oxidizing agent 3) Reduced, and becomes the reducing agent
2) Oxidized, and becomes the reducing agent 4) Reduced, and becomes the oxidizing agent

5. Consider the half-reaction equation below?
-
0
Li --------------- Li + e
0
The Li is
1) Oxidized, and becomes the reducing agent 3) Oxidized, and becomes the oxidizing agent
2) Reduced, and becomes the reducing agent 4) Reduced, and becomes the reducing agent

6. Given the following half-reaction equation
-
-
Cl2 + 2e ------- 2Cl
Each chlorine atom
1) Loses an electron, and its oxidation number increases
2) Loses an electron, and its oxidation number decreases
3) Gains an electron, and its oxidation number increases
4) Gains an electron, and its oxidation number decreases

7. In the half-reaction equation
3+
2+
Fe ------------ Fe + e -
Which is true of the Fe 2+?

1) It gains an electron and becomes an ion with a greater charge
2) It gains an electrons and becomes an ion with a smaller charge

3) It loses an electrons and becomes an ion with a greater charge

4) It loses an electrons and becomes an ion with a smaller charge

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