Which row correctly describes oxidation in terms of oxygen, electrons and oxidation state?
| oxygen is | electrons are | oxidation state is |
A | added | added | increased |
B | added | lost | increased |
C | lost | added | decreased |
D | lost | lost | decreased |
Did this page help you?
Magnesium reacts with iron(III) oxide in the following reaction.
magnesium + iron(III) oxide → magnesium oxide + iron
Which statement about this reaction is correct?
Magnesium oxide is reduced
Iron is oxidised
Magnesium is oxidised
Iron(III) oxide is oxidised
Did this page help you?
When copper is heated in air, its surface turns black.
What is happening to the copper in this reaction?
Copper undergoes thermal decomposition
Copper is oxidised
Copper burns with a lilac flame
Copper is reduced
Did this page help you?
Lead(II) oxide undergoes a number of different redox reactions.
In which of the following reactions is lead(II) oxide, PbO, not reduced?
PbO + Zn → Pb + ZnO
PbO + H2 → Pb + H2O
PbO + C → Pb + CO
2PbO + O2 → 2PbO2
Did this page help you?
The following equations are all examples of redox reactions.
In which equation is the underlined substance being oxidised?
CO2 + C → 2CO
FeO + Mg → MgO + Fe
3CO + Fe2O3 → 2Fe + 3CO2
CuCO3 → CuO + CO2
Did this page help you?
Three reactions are shown below.
NO + O3 → NO2 + O2
2C + O2 → 2CO
2MgO + O2 → 2MgO2
Which row correctly describes the process each reactant molecule undergoes?
| NO | O3 | MgO |
A | oxidised | reduced | oxidised |
B | oxidised | oxidised | reduced |
C | reduced | oxidised | oxidised |
D | reduced | reduced | oxidised |
Did this page help you?
What is the oxidation state of Fe in Fe2O3?
+2
-2
-3
+3
Did this page help you?
Which row correctly describes the process of reduction in terms of oxygen, electrons and oxidation state?
| oxygen is | electrons are | oxidation state is |
A | lost | added | unchanged |
B | added | lost | increased |
C | lost | added | decreased |
D | added | lost | increased |
Did this page help you?
Which row correctly names each compound?
| CuSO4 | KMnO4 | FeCl3 |
A | copper sulfate | potassium manganate (IV) | iron(II) chloride |
B | copper sulfate | potassium manganate (V) | iron(III) chloride |
C | copper(II) sulfate | potassium manganate (VI) | iron(II) chloride |
D | copper(II) sulfate | potassium manganate (VII) | iron(III) chloride |
Did this page help you?
Potassium iodide is used to test for the presence of oxidising agents. Which row correctly describes what happens when potassium iodide is added to an acidified solution containing an oxidising agent?
| colour change | reason for colour change |
A | turns brown | iodine is used up |
B | turns brown | iodine is formed |
C | turns yellow | iodine is used up |
D | no colour change | iodine is formed |
Did this page help you?
In which equations is the change in the underlined species correct?
1 only
2 only
1 and 3
2 and 3
Did this page help you?
Iron(II) ions react with chlorine.
2Fe2+(aq) + Cl2(g) → 2Fe3+(aq) + 2Cl−(aq)
Which statement about this reaction is correct?
Chlorine is reduced by iron(II) ions.
Chlorine is the reducing agent.
Iron(II) ions are reduced by chlorine.
Iron(II) ions are the oxidizing agent.
Did this page help you?
Which reactions involve oxidation and reduction?
1 | chlorine gas reacting with aqueous potassium iodide |
2 | dilute sulfuric acid reacting with magnesium |
3 | dilute hydrochloric acid reacting with aqueous sodium hydroxide |
1, 2 and 3
1 and 2 only
1 and 3 only
2 and 3 only
Did this page help you?
A series of redox reactions are shown. What is the oxide that undergoes oxidation?
1 | 2CO + 2NO → 2CO2 + N2 |
2 | Fe2O3 + 2Al → Al2O3 + 2Fe |
3 | 2ZnO + C → 2Zn + CO2 |
4 | Fe2O3 + 3CO → 2Fe + 3CO2 |
CO
C
NO
Fe2O3
Did this page help you?
In which reaction is the reactant being reduced?
Mg → Mg2+ + 2ē
Mg2+ + 2ē → Mg
CrO → Cr2O3
C → CO2
Did this page help you?
Vanadium is a transition element and forms several oxides. In which of the following reactions does vanadium undergo oxidation?
V2O3 → VO
V2O5 → VO2
V2O3 → V2O5
VO2 → V2O3
Did this page help you?
Manganese is a transition element and forms several oxides. In which of the following changes does manganese undergo reduction?
Mn2O3 → Mn2O7
MnO → MnO3
Mn2O2 → MnO
MnO → Mn
Did this page help you?
Potassium manganate (VII) is used to test for the presence of reducing agents. Which row correctly describes what happens when acidified potassium manganate (VII) is added to a solution containing a reducing agent?
| colour change | reason for colour change |
A | pink/purple to colourless | MnO4- is oxidised |
B | pink/purple to colourless | MnO4- is reduced |
C | colourless to pink/purple | MnO4- is oxidised |
D | colourless to pink/purple | MnO4- is reduced |
Did this page help you?
Which row correctly describes an oxidising agent and a reducing agent?
| oxidising agent | reducing agent |
A | adds oxygen to a substance | removes oxygen from a substance |
B | adds oxygen to a substance | increases the oxidation number of a substance |
C | removes oxygen from a substance | adds oxygen to a substance |
D | decreases the oxidation number of a substance | increases the oxidation number of a substance |
Did this page help you?
Which one of the following substances is commonly used as a reducing agent?
H2SO4
KMnO4
H2O2
CO
Did this page help you?
In which two of the following redox reactions is the substance in bold acting as a reducing agent?
1 | CuO + H2 → Cu + H2O |
2 | 2Ca + O2 → 2CaO |
3 | CO + CuO → Cu + CO2 |
4 | CO2 + C → 2CO |
1 and 2 only
1 and 3 only
2 and 3 only
All of them
Did this page help you?
Hydrogen and copper(II) oxide react to produce copper metal and water.
CuO + H2 → Cu + H2O
Which row correctly describes the oxidising agent and reducing agent?
| oxidising agent | reducing agent |
A | H2O | Cu |
B | H2 | CuO |
C | Cu | H2O |
D | CuO | H2 |
Did this page help you?