Redox
1.
2.
3.
4.
In the following, give the oxidation number for the indicated atoms.
a.
S in Na2SO3
d.
C in Na2CO3
g.
S in H2S2O7
b.
Mn in KMnO4
e.
N in NO2
h.
S in Al2S3
c.
N in Ca(NO3)2
f.
S in HSO4
i.
Mn in MnCl2
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Some of the following unbalanced reactions are oxidation-reduction reactions, and some are
not. In each case is the reaction redox? If yes, name the element reduced, the element
oxidized, the oxidizing agent, and the reducing agent.
a.
BaCl2 + Na2SO4 ¼ NaCl + BaSO4
i.
HNO3 + H3PO3 ¼ NO + H3PO4 + H2O
b.
H2 + N2 ¼ NH3
j.
HNO3 + I2 ¼ HIO3 + NO2 + H2O
c.
C + H2O ¼ CO + H2
k.
Na2S + AgNO3 ¼ Ag2S + NaNO3
d.
AgNO3 + FeCl3 ¼ AgCl + Fe(NO3)3
l.
H+ + NO3- + Fe2+ ¼ H2O + NO + Fe3+
e.
H2CO3 ¼ H2O + CO2
m. FeBr2 + Br2 ¼ FeBr3
f.
MgSO4 + Ca(OH)2 ¼ Mg(OH)2 + CaSO4
n.
S2O32- + I2 ¼ S4O62- + I-
g.
H2O2 + PbS ¼ PbSO4 + H2O
o.
H2O2 + MnO4- ¼ O2 + Mn2+
h.
KCl + H2SO4 ¼ KHSO4 + HCl
p.
Zn + MnO2 + NH4Cl ¼ZnCl2 + Mn2O3 + NH3 + H2O
Balance the following equations using half reactions. Identify the oxidation half reactions and
the reduction half reactions.
a.
Cr2O72- + H+ + I- ¼ Cr3+ + I2 + H2O
f.
MnO4- + H2SO3 + H+ ¼ Mn2+ + HSO4- + H2O
b.
As2O3 + H+ + NO3- + H2O ¼ H3AsO4 + NO
g.
I2 + H2SO3 + H2O ¼ I- + HSO4- + H+
c.
H3AsO4 + Zn ¼ AsH3 + Zn2+
h.
HgS + Cl- + NO3- ¼ HgCl42- + S + NO
d.
MnO42- + H+ ¼ MnO4- + MnO2
i.
NO2 + OH- ¼ NO2- + NO3-
e.
MnO4- + SO2 ¼ Mn2+ + SO42- + H+
j.
S + H+ + NO3- ¼ SO2 + NO + H2O
Balance the following equations after putting them in ionic form.
a.
Cu(s) + HNO3(aq) ¼ Cu(NO3)2(aq) + NO(g) + H2O(l)
b.
Fe(NO3)2(aq) + HNO3(aq) ¼ Fe(NO3)3(aq) + NO(g) + H2O(l)
c.
Zn(s) + HNO3(aq) ¼ Zn(NO3)2(aq) + NO2(g) + H2O(l)
d.
Sb(s) + H2SO4(aq) ¼ Sb2(SO4)3(aq) + SO2(g) + H2O(l)
e.
H2S(g) + H2SO3(aq) ¼ S(s) + H2O(l)
f.
HCl(aq) + HNO3(aq) ¼ HClO(aq) + NO(g)
g.
Ag(s) + HClO3(aq) + HCl(aq) ¼ AgCl(s) + H2O(l)
h.
KI(aq) + O2(g) ¼ KI3(aq) + H2O(l)
i.
HNO3(aq) + H2SO4(aq) + Hg(l) ¼ Hg2SO4(s) + NO(g) + H2O(l)
j.
CO(g) + I2O5(g) ¼ CO2(g) + I2(g)