Name: _________________________
Oxidation and Reduction
1. What is the oxidation state of nitrogen in the
compound NH4Br?
(1) –1
(2) +2
(3) –3
(4) +4
2. Given the balanced equation representing a
reaction:
2KClO 3(s)
2KCl(s) + 3O 2(g)
The oxidation state of chlorine in this reaction
changes from
(1) –1 to +5
(3) +5 to –1
(2) + l to –1
(4) –1 to +1
Date: ________________
9. Which changes occur when Pt2+ is reduced?
(1) The Pt 2+ loses electrons and its oxidation
number decreases.
(2) The Pt 2+ gains electrons and its oxidation
number increases.
(3) The Pt 2+ gains electrons and its oxidation
number decreases.
(4) The Pt 2+ loses electrons and its oxidation
number increases.
10. Given the balanced ionic equation representing a
reaction:
3. What is the oxidation number of chromium in the
chromate ion, CrO 42– ?
(1) +8
(2) +6
(3) +2
(4) +3
4. In which compound does chlorine have the highest
oxidation number?
(1) NaClO 4
(3) NaClO 2
(2) NaClO
(4) NaClO 3
5. In an oxidation-reduction reaction, the number of
electrons lost is
(1)
(2)
(3)
(4)
equal to the number of protons gained
equal to the number of electrons gained
less than the number of electrons gained
less than the number of protons gained
6. The chemical process in which electrons are
gained by an atom or an ion is called
(1) substitution
(3) oxidation
(2) addition
(4) reduction
7. An oxidation-reduction reaction involves the
(1)
(2)
(3)
(4)
sharing of electrons
transfer of protons
transfer of electrons
sharing of protons
8. Which half-reaction correctly represents reduction?
(1)
(2)
(3)
(4)
Mn 4+ + e – ® Mn 3+
Mn 4+ + 3e – ® Mn 7+
Mn 4+ ® Mn 7+ + 3e –
Mn 4+ ® Mn 3+ + e –
In this reaction, electrons are transferred from
(1)
(3)
to
to Mg2+
(2)
(4)
to
to
11. Given the balanced ionic equation:
2Al(s) + 3Cu2+(aq)
2Al 3+(aq) + 3Cu(s)
Compared to the total charge of the reactants. the
total charge of the products is
(1) greater
(3) the same
(2) less
12. The oxidation number of a reducing agent can
change from
(1) –1 to –3
(3) 3 to –1
(2) –2 to –1
(4) 4 to –3
13. Which ion is most easily reduced?
(1) Ca2+
(3) Zn2+
(2) Co2+
(4) Mg 2+
14. Given the redox reaction:
Fe2+(aq) + Zn(s) ® Zn2+(aq) + Fe(s)
Which species acts as a reducing agent?
(1) Zn2+(aq)
(3) Fe 2+(aq)
(2) Fe(s)
(4) Zn(s)
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15. In a redox reaction, the species reduced
(1)
(2)
(3)
(4)
gains electrons and is the reducing agent
loses electrons and is the oxidizing agent
loses electrons and is the reducing agent
gains electrons and is the oxidizing agent
16. In a redox reaction, a reducing agent will always
(1) gain protons
(3) lose electrons
(2) gain electrons
(4) lose protons
17. Given the balanced ionic equation representing a
reaction:
2Al(s) + 3Cu2+(aq)
2Al 3+(aq) + 3Cu(s)
Which half-reaction represents the reduction that
occurs?
(1)
(2)
(3)
(4)
Al 3+ + 3e – Al
Cu2+ + 2e –
Cu
2+
Cu
Cu + 2e –
Al
Al 3+ + 3e –
18. Given the balanced equation representing a redox
reaction:
2Al + 3Cu2+ ® 2Al3+ + 3Cu
Which statement is true about this reaction?
(1)
(2)
(3)
(4)
Each Al3+ gains 2e– and each Cu loses 3e –.
Each Al loses 2e – and each Cu 2+ gains 3e–.
Each Al3+ gains 3e– and each Cu loses 2e –.
Each Al loses 3e – and each Cu 2+ gains 2e–.
19. Which reaction occurs spontaneously?
(1)
(2)
(3)
(4)
Cl 2(g) + 2NaBr(aq)
Br 2( ) + 2NaCl(aq)
Cl 2(g) + 2NaF(aq) F2(g) + 2NaCl(aq)
I 2(s) + 2NaF(aq) F2(g) + 2NaI(aq)
I 2(s) + 2NaBr(aq) Br 2( ) + 2NaI(aq)
20. Which metal is more active than H 2?
(1) Ag
(2) Cu
(3) Au
(4) Pb
21. Which type of reaction is occurring when a metal
undergoes corrosion?
(1)
(2)
(3)
(4)
saponification
oxidation-reduction
neutralization
polymerization
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