Name: ____________________
CLASS/SEAT#: _________
Oxidation and Reduction
YECA CHEMISTRY
1. What is the oxidation state of nitrogen in the
compound NH4Br?
(1) –1
(2) +2
(3) –3
(1) –4
(2) –2
(3) +2
(4) +4
3. In which compound is the oxidation number of
oxygen treated as -1?
(1) H2O (2) H2O2 (3) CO
10. Given the equation:
2 Al + 3 Cu2+ ® 2 Al3+ + 3 Cu
(4) +4
2. What is the oxidation number of Pt in K2PtCl 6?
The reduction half-reaction is
(1) Cu2+ + 2e - ® Cu (3) Al ® Al 3+ + 3e (2) Al + 3e - ® Al 3+ (4) Cu2+ ® Cu + 2e11. Given the reaction:
(4) CO 2
Zn(s) + 2 HCl(aq) ® ZnCl2(aq) + H2(g)
4. What is the oxidation number of carbon in NaHCO3?
(1) –2
(2) +2
(3) –4
(4) +4
5. In which substance is the oxidation number of
nitrogen zero?
(1) NO 2 (2) N2O (3) NH 3 (4) N2
6. In which compound does hydrogen have an oxidation
state of –1?
(1) H2O (2) NH 3 (3) NaH (4) HCl
7. A redox reaction always involves
(1)
(2)
(3)
(4)
a change in oxidation number
the transfer of protons
a change of phase
the formation of ions
8. In a redox reaction, how does the total number of
electrons lost by the oxidized substance compare to
the total number of electrons gained by the reduced
substance?
(1) The number lost is always greater than the
number gained.
(2) The number lost is always equal to the number
gained.
(3) The number lost is sometimes equal to the
number gained.
(4) The number lost is sometimes less than the
number gained.
9. In a redox reaction, the reducing agent will
(1)
(2)
(3)
(4)
gain electrons and be oxidized
lose electrons and be oxidized
lose electrons and be reduced
gain electrons and be reduced
CID: __________
DATE: _________
Which equation represents the correct oxidation
half-reaction?
(1)
(2)
(3)
(4)
Zn(s) ® Zn2+ + 2e –
Zn2+ + 2e ® Zn(s)
2 Cl – ® Cl 2(g) + 2e–
2 H + 2e– ® H2(g)
12. Which balanced equation represents a redox
reaction?
(1)
(2)
(3)
(4)
CuO + CO ® Cu + CO2
BaCl2 +K2CO 3 ® BaCO 3 +2KCl
HCl + KOH ® KCl + H 2O
AgNO3 + NaCl ® AgCl + NaNO 3
13. According to Reference Table J, which of these
metals will react most readily with 1.0 M HCl to
produce H 2(g)?
(1) K
(2) Zn
(3) Ca
(4) Mg
14. Based on Reference Table J, which of the following
elements will replace Pb from Pb(NO 3) 2(aq)?
(1) Au(s)
(2) Ag(s)
(3) Mg(s)
(4) Cu(s)
15. Due to it having a low activity, which element can
be found in nature in the free (uncombined) state?
(1) Ba
(2) Au
(3) Al
(4) Ca
Oxidation and Reduction
16. Iron corrodes according to the equation
4 Fe + 3 O2 ® 2 Fe2O3.
This redox process occurs because
(1)
(2)
(3)
(4)
oxygen loses electrons and is reduced
iron gains electrons and is reduced
oxygen gains electrons and is oxidized
iron loses electrons and is oxidized
20. Reduction occurs at the cathode in
(1)
(2)
(3)
(4)
voltaic cells, only
both electrolytic cells and voltaic cells
neither electrolytic cells nor voltaic cells
electrolytic cells, only
21. The diagram below represents an electrochemical
cell.
17. Which energy change occurs in an operating voltaic
cell?
(1)
(2)
(3)
(4)
chemical to nuclear
electrical to chemical
nuclear to chemical
chemical to electrical
18. The diagram below represents a chemical cell.
What occurs when the switch is closed?
(1)
(2)
(3)
(4)
Electrons flow from Cu to Zn.
Cu is oxidized.
Electrons flow from Zn to Cu.
Zn is reduced.
22. The diagram below shows the electrolysis of fused
KCl.
In order for the cell to operate, it should be provided
with
(1)
(2)
(3)
(4)
an external path for electrons
a salt bridge
an anode
a cathode
19. In a chemical cell composed of two half-cells, ions
are allowed to flow from one half-cell to another by
means of
(1)
(2)
(3)
(4)
an external conductor
electrodes
a salt bridge
a voltmeter
What occurs when the switch is closed?
(1) Positive ions migrate toward the anode, where
they gain electrons.
(2) Positive ions migrate toward the anode, where
they lose electrons.
(3) Positive ions migrate toward the cathode,
where they lose electrons.
(4) Positive ions migrate toward the cathode,
where they gain electrons.
Oxidation and Reduction
23. Which energy conversion occurs in an operating
electrolytic cell?
(1)
(2)
(3)
(4)
nuclear energy to thermal energy
thermal energy to nuclear energy
electrical energy to chemical energy
chemical energy to electrical energy
Base your answers to questions 24 and 25 on the
diagram below which represents the electroplating of
a metal fork with Ag(s).
24. Which equation represents the half-reaction that
takes place at the fork?
(1)
(2)
(3)
(4)
Ag(s) ® Ag+ + e –
Ag+ + NO 3– ® AgNO3
AgNO3 ® Ag+ + NO 3–
Ag+ + e – ® Ag(s)
25. Which part of the electroplating system is provided
by the fork?
(1)
(2)
(3)
(4)
the cathode, which is the negative electrode
the cathode, which is the positive electrode
the anode, which is the positive electrode
the anode, which is the negative electrode