soal latihan redox
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Materi reduksi-oksidasiTRANSCRIPT
SOAL LATIHAN
1. For the following reactions, identify the substance oxidized, the substance reduced, the oxidizing agent, and the reducing agenta).Cu + 2H2SO4 CuSO4 + SO2 + H2Ob).3SO2 + 2HNO3 + 2H2O 3H2SO4 + 2NOc). 5H2SO4 + 4Zn 4ZnSO4 + H2S + 4H2Od).I2 + 10HNO3 2HIO3 + 10NO2 + 4H2Oe).2KMnO4 + 5H2C2O4 + 3H2SO4 10CO2 + K2SO4 + 2MnSO4 + 8H2O
2. A pollutan in smog is nitrogen dioxide, NO2. They has a reddish brown color and is responsible for the red brown color associated with this type of air pollution. Nitrogen dioxide is also a contributor to acid rain because when rain passes through air contaminated with NO2, it dissolve and undergoes the following reaction :
3NO2(g) + H2O NO(g) + 2H+(aq) + 2NO3(aq)In this reaction, which element is reduced and which is oxidized?
3. Balance the following half reactions. Indicate whether each is an oxidation or reductiona).BiO3
- Bi3+ (acidic solution)b).Pb2+ PbO2 (acidic solution)c). Mn(OH)2 MnO4
2- (basic solution)d).H4IO6
- I2 (basic solution)
4. Balance the following equation for reactions occuring in an acidic solution :a).S2O3
2- + OCl- Cl- + S4O62-
b).NO3- + Cu NO2 + Cu2+
c). IO3- + AsO3
3- I + AsO43-
d).Cr3+ + BiO3- Cr2O72- + Bi3+
e).VO2+ + Sn2+ VO2+ + Sn4+
f). C2O42- + HNO2 CO2 + NO
g).XeF2 + Cl- Xe + F- + Cl2
5. Balance the following equation for reactions occuring in an basic solution :a).Cr2O4
2- + S2- S + CrO2-
b).MnO4 + C2O42- CO2 + MnO2
c). NiO2 + Mn(OH)2 SO42- + MnO2
d).Cr2O2- + S2O8
2- CrO42- + SO4
2-
e).O2 + CrO42- SO4
2- + CrO2
f). SO32- + CrO4
2- SO42- + CrO2
6. Laundry bleach such as Clorox is a dilute solution of sodium hypochlorite, NaOCl. Write the balanced net ionic equation for the reaction of NaOCl with Na2S2O3. The OCl- is reduced to chloride ion and the S2O3
2- oxidized to sulfate ion.
Balancing redox equation by ion-electron method (in acidic solution)
A. NO3- + Cu NO2 + Cu2+
1). Divide the skeleton equation into two half-reactions. One involves oxidation and
the other involves reduction
Oxidation......................................................................................................... :
Reduction........................................................................................................ :
2). Balance all atoms other than H and O
Oxidation......................................................................................................... :
Reduction ....................................................................................................... :
3). Balance oxygen atom by adding H2O to the side that requires O atom
Oxidation......................................................................................................... :
Reduction........................................................................................................ :
4). Balance hydrogen by adding H+ to the side that requires H
Oxidation......................................................................................................... :
Reduction........................................................................................................ :
5). Balance the charge by adding electrons
Oxidation......................................................................................................... :
Reduction........................................................................................................ :
6). Maka the number of electrons accepted in reduction half-reaction equal to the
number of electrons released in oxidation half-reaction
Oxidation......................................................................................................... :
Reduction........................................................................................................ :
7). Add the balanced two half-reactions
Oxidation......................................................................................................... :
Reduction........................................................................................................ :
..........................................................................................................................
B. H3AsO3 + Cr2O72- H3AsO4 + Cr3+
1). Divide the skeleton equation into two half-reactions. One involves oxidation and
the other involves reduction
Oxidation......................................................................................................... :
Reduction........................................................................................................ :
2). Balance all atoms other than H and O
Oxidation......................................................................................................... :
Reduction ....................................................................................................... :
3). Balance oxygen atom by adding H2O to the side that requires O atom
Oxidation......................................................................................................... :
Reduction.......................................................................................:
4). Balance hydrogen by adding H+ to the side that requires H
Oxidation......................................................................................................... :
Reduction........................................................................................................ :
5). Balance the charge by adding electrons
Oxidation........................................................................................:
Reduction........................................................................................................ :
6). Maka the number of electrons accepted in reduction half-reaction equal to the
number of electrons released in oxidation half-reaction
Oxidation......................................................................................................... :
Reduction........................................................................................................ :
7). Add the balanced two half-reactions
Oxidation......................................................................................................... :
Reduction........................................................................................................ :
..........................................................................................................................
Balancing redox equation by ion-electron method (in basic solution)
A. ClO3- + N2H4 NO + Cl-
1). Divide the skeleton equation into two half-reactions. One involves oxidation
and the other involves reduction
Oxidation....................................................................................................... :
Reduction...................................................................................................... :
2). Balance all atoms other than H and O
Oxidation....................................................................................................... :
Reduction ..................................................................................................... :
3). Balance oxygen atom by adding H2O to the side that requires O atom
Oxidation....................................................................................................... :
Reduction...................................................................................................... :
4). Balance hydrogen by adding H+ to the side that requires H
Oxidation....................................................................................................... :
Reduction...................................................................................................... :
5). Balance the charge by adding electrons
Oxidation....................................................................................................... :
Reduction...................................................................................................... :
6). Maka the number of electrons accepted in reduction half-reaction equal to the
number of electrons released in oxidation half-reaction
Oxidation....................................................................................................... :
Reduction...................................................................................................... :
7). Add the balanced two half-reactions
Oxidation....................................................................................................... :
Reduction...................................................................................................... :
........................................................................................................................
8). Add two both sides of the equation the same number of OH- as there H+
Oxidation......................................................................................:
Reduction...................................................................................................... :
........................................................................................................................
9). Combine H+ and OH- to form H2O
Oxidation....................................................................................................... :
Reduction...................................................................................................... :
........................................................................................................................
10). Cancel any H2O that appears on both sides of the balanced equation
Oxidation....................................................................................................... :
Reduction...................................................................................................... :
........................................................................................................................
B. O2 + N2H4 H2O2 + N2
1). Divide the skeleton equation into two half-reactions. One involves oxidation
and the other involves reduction
Oxidation....................................................................................................... :
Reduction.....................................................................................:
2). Balance all atoms other than H and O
Oxidation....................................................................................................... :
Reduction ..................................................................................................... :
3). Balance oxygen atom by adding H2O to the side that requires O atom
Oxidation....................................................................................................... :
Reduction...................................................................................................... :
4). Balance hydrogen by adding H+ to the side that requires H
Oxidation....................................................................................................... :
Reduction...................................................................................................... :
5). Balance the charge by adding electrons
Oxidation....................................................................................................... :
Reduction...................................................................................................... :
6). Maka the number of electrons accepted in reduction half-reaction equal to the
number of electrons released in oxidation half-reaction
Oxidation....................................................................................................... :
Reduction...................................................................................................... :
7). Add the balanced two half-reactions
Oxidation....................................................................................................... :
Reduction...................................................................................................... :
........................................................................................................................
8). Add two both sides of the equation the same number of OH- as there H+
Oxidation....................................................................................................... :
Reduction...................................................................................................... :
........................................................................................................................
9). Combine H+ and OH- to form H2O
Oxidation......................................................................................:
Reduction...................................................................................................... :
........................................................................................................................
10). Cancel any H2O that appears on both sides of the balanced equation
Oxidation....................................................................................................... :
Reduction...................................................................................................... :
........................................................................................................................
