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Topic 11: Redox and electrochemistry
.

11. Half-reactions: Determining oxidation and reduction half-reaction equations

1. Which half-reaction equation correctly represents oxidation?
2+
-

1) Mg + 2e ------- Mg

2) Mg + 2e ----- Mg
-
2+
2+
3) Mg ------------------ Mg + 2e - -
2+
4) Mg -------------------- Mg + 2e

2. Which half-reaction correctly represents oxidation?
-
1) F2 ---------------- 2F + 2e -
-
-
2) F2 + 2e ---------- 2F -
+
3) H2 ------------------- 2H + 2e
-
4) H2 + 2e ----------- 2 H -

3. Which half-reaction correctly shows reduction?
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1) Sn + 2e --------- Sn
2+
0
-
4+
-
2+
2) Sn ------------------- Sn + 2e
-
2+
4+
3) Sn + 2e ---------- Sn -
0
2+
4) Sn ------------------- Sn + 2e

4. Which half-reaction correctly represents oxidation?
-
-

1) 3Ag + 3e ---------- 3 Ag
2) 3Ag -------------------- 3Ag + 3e -
+
-
3+
3) Au + 3e --------- Au -
3+
4) Au ------------------ Au + 3e

5. Which half-reaction equation correctly represents a reduction reaction?
+
-
0

1) Li + e ----------- Li
2) Na + e ------------ Na
-
+
0
0
-
3) Br2 + 2e ---------- 2Br - -
0
-
4) Cl2 + e ---------- 2Cl

6. Which half-reaction correctly represents a reduction reaction?
3+
5+
-
1) Nb + 2e ----------- Nb -
0
3+
2) Nb ------------------- Nb + 3e
7+
4+
3) Mn ------------------- Mn + 3e -
4+
-
4) Mn + 3e --------- Mn 7+

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