REDOX REACTION QUIZ Part I

1.Which substance is being oxidized in the following reaction?
2HCl(aq) + Zn(s)  ZnCl2(aq) + H2(g)
a) H+(aq) ions
b) Cl-(aq) ions
c) Zn(s)
d) Zn2+(aq) ions
e) H2(g)
2.What is the oxidation number of Cr in K2Cr2O7?
a) +2
b) +3
c) +5
d)+6
e)+7
3.Given the following incomplete redox reaction, balance this equation in ACID solution with the set of smallest whole number coefficient:
Zn(s) + NO3-(aq)  Zn2+(aq) + N2(g)
Identify the CORRECT statement below:
a) Zn(s) and NO3- react in a 1 to 2 mole ratio, respectively.
b) Zn(s) and NO3- react in a 5 to 2 mole ratio, respectively.
c) Zn(s) and NO3- react in a 2 to 5 mole ratio, respectively.
d) Zn(s) and NO3- react in a 5 to 1 mole ratio, respectively.
4.Which oxidation number is INCORRECTLY identified?
a) the oxidation number of P in phosphorus acid, H3PO3is +5
b) the oxidation number of H in sodium hydride NaH is -1
c) the oxidation number of O in water is -2
d) the oxidation number of Mn in manganic acid, HMnO4 is +7
5.Which of the following is the INCORRECT statement?
a) Oxidation results in an increase in oxidation number.
b) Electrons are being transferred in a redox reaction.
c) The oxidizing agent in a redox reaction is oxidized.
d) Reduction is a gain of electrons.
6.In the reaction below, the oxidizing agent is ….
2NaCl + 2H2SO4 + MnO2 → Na2SO4 + MnSO4 + 2H2O + Cl2
a)Na+
b)Mn4+
c)Cl-
d)H+
e)O2-
7.Which substance is being reduced in the following reaction?
14H+(aq) + Cr2O72- (aq) + 6Fe2+(aq)  2Cr3+(aq) + 6Fe3+(aq) + 7 H2O
a) H+(aq)
b) Fe2+(aq)
c) H2O
d) Cr3+(aq)
e) Cr2O72-
8.Given the reaction:
4 HCl(aq) + MnO2(s) MnCl2(aq) + 2 H2O(l) + Cl2(g)
The manganese is ….
a) reduced and its oxidation number changes from +4 to +2
b) reduced and its oxidation number changes from +2 to +4
c) oxidized and its oxidation number changes from +4 to +2
d) oxidized and its oxidation number changes from +2 to +4
9.Given the reaction:
Pb(s) + Cu2+(aq)  Pb2+(aq) + Cu(s)
What is the reducing agent?
a) Pb2+(aq)
b) Cu2+(aq)
c) Pb(s)
d) Cu(s)
e) Pb(s) and Cu(s)
10.What occurs when an atom is oxidized in a chemical reaction?
a) a loss of electrons and a decrease in oxidation number
b) a loss of electrons and an increase in oxidation number
c) a gain of electrons and a decrease in oxidation number
d) a gain of electrons and an increase in oxidation number
11.Given the reaction:
3 Sn4+(aq) + 2 Cr(s)  3 Sn2+(aq) + 2 Cr3+(aq)
Which half-reaction represents the reduction that occurs?
a) Sn4+(aq) + 2 e-  Sn2+(aq)
b) Sn2+(aq)  Sn4+(aq) + 2 e-
c) Cr(s)  Cr3+(aq) + 3 e-
d) Cr3+(aq) + 3 e-  Cr(s)
12.Given the reaction:
Zn(s) + 2 HCl(aq)  ZnCl2(aq) + H2(g)
Which substance is oxidized?
a) Zn(s)
b) HCl(aq)
c) Cl-(aq)
d) H+(aq)
e) H2(g)
13.A redox reaction always demonstrates the conservation of ….
a) mass, only
b) charge, only
c) both mass and charge
d) neither mass nor charge
e) mass, volume, and charge
14.Given the redox reaction:
Mg(s) + CuSO4(aq) MgSO4(aq) + Cu(s)
Which species acts as the oxidizing agent?
a) Cu(s)
b) Cu2+(aq)
c) Mg(s)
d) Mg2+(aq)
e) SO42-
15.Which of the following ions is the weakest oxidizing agent?
a) Au3+
b) Cr3+
c) Hg2+
d) Ba2+
e) Mg2+