31 questions · 31 marks · ≈ 31 min
Which row describes oxidation and reduction in terms of the transfer of electrons and changes in oxidation number?
| Transfer of electrons | Change in oxidation number | |||
|---|---|---|---|---|
| Oxidation | Reduction | Oxidation | Reduction | |
| A | Gain | Loss | Increase | Decrease |
| B | Loss | Gain | Increase | Decrease |
| C | Loss | Gain | Decrease | Increase |
| D | Gain | Loss | Decrease | Increase |
Choose your answer
The heptahydrate mineral of magnesium sulfate is used in Epsom salts for preparing therapeutic baths.
What is the sum of all the oxidation numbers in MgSO4?
Choose your answer
-2
+2
+7
0
Which row gives the most common oxidation numbers of fluorine, oxygen and hydrogen in compounds?
| F | O | H | |
|---|---|---|---|
| A | +7 | −1 | −1 |
| B | +1 | +2 | +1 |
| C | −1 | −1 | −1 |
| D | −1 | −2 | +1 |
Choose your answer
Solutions containing chlorate ions decompose on heating as shown:
3ClO- (aq) → ClO3- (aq) + 2Cl- (aq)
Which row gives the oxidation number of the chlorine in each ion?
| ClO- | ClO3- | Cl- | |
|---|---|---|---|
| A | +1 | +5 | −1 |
| B | +1 | +3 | −1 |
| C | −1 | +5 | −1 |
| D | −1 | +3 | −1 |
Choose your answer
A student added a solution of iodine to a solution of sodium bromide.
Which statement correctly describes what happens?
Choose your answer
No reaction occurs.
The bromide ions are oxidised.
The iodine molecules are oxidised.
Both the bromide ions and iodine molecules undergo changes in their oxidation state.
Which equation has the smallest change in oxidation number for nitrogen?
Choose your answer
N2H4 (g) + 3O2 (g) → 2NO2 (g) + 2H2O (g)
3Mg (s) + N2 (g) → Mg3N2 (s)
4NH3 (g) + 5O2 (g) → 4NO (g) + 6H2O (g)
2NO (g) + O2 (g) → 2NO2 (g)
In the compound [ICl2]+[SbCl6]−, the oxidation number of chlorine is −1.
Which row gives the oxidation numbers of I and Sb in the compound?
| I | Sb | |
|---|---|---|
| A | +1 | +5 |
| B | +1 | +7 |
| C | +3 | +5 |
| D | +3 | +7 |
Choose your answer
Titanium dioxide is obtained from the ore ilmenite, FeTiO3, in which iron has an oxidation number of +2.
FeTiO3 (s) → TiO2 (s)
What is the change in the oxidation number of titanium in the reaction?
Choose your answer
+4 to +5
+3 to +4
No change
+6 to +4
Which compound has the highest oxidation number of nitrogen?
Choose your answer
N2O
NO
NaNO2
N2O4
Which reaction represents have the largest change in oxidation number of an element?
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Cr2O72- (aq) + 6Fe2+ (aq) + 14H+ (aq) → 2Cr3+ (aq) + 6Fe3+ (aq) + 7H2O (l)
3ClO- (aq) → ClO3- (aq) + 2Cl- (aq)
5Fe2+ (aq) + MnO4- (aq) + 8H+ (aq) → 5Fe3+ (aq) + Mn2+ (aq) + 4H2O (l)
PbO2 (s) + Sn2+ (aq) + 4H+ (aq) → Sn4+ (aq) + Pb2+ (aq) + 2H2O (l)
Sulfur dioxide and oxygen difluoride react together.
SO2 (g) + OF2 (g) → SO3 (g) + F2 (g)
Which row is correct?
| sulfur | fluorine | oxygen in OF2 | |
|---|---|---|---|
| A | Oxidised | Reduced | Reduced |
| B | Reduced | Oxidised | Reduced |
| C | Oxidised | Oxidised | Reduced |
| D | Reduced | Oxidised | Oxidised |
Choose your answer
Chlorine and hot aqueous sodium hydroxide react to produce chloride ions, chlorate(V) ions and water.
Which row gives the values of the coefficients p, r and s in the equation?
pCl2 (g) + qOH− (aq) → rCl− (aq) + sClO3− (aq) + tH2O (l)
| p | r | s | |
|---|---|---|---|
| A | 3 | 5 | 1 |
| B | 3 | 4 | 2 |
| C | 2 | 3 | 1 |
| D | 4 | 6 | 2 |
Choose your answer
Which statement about the redox chemistry of the halogens is correct?
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Bromine can oxidise chloride ions.
Iodide ions are the weakest reducing agents of the first four Group 17 ions.
In reactions with water, chlorine is oxidised and reduced.
Fluorine is a weaker oxidising agent than chlorine.
Which reaction shows the species in bold acting as an oxidising agent?
Choose your answer
Cr2O72- (aq) + 8H+ (aq) + 3SO32- (aq) → 2Cr3+ (aq) + 4H2O (l) + 3SO42- (aq)
Mg (s) + Fe2+ (aq) → Mg2+ (aq) + Fe (s)
Cl2 (aq) + 2Br- (aq) → 2Cl- (aq) + Br2 (aq)
Fe2O3 (s) + 3CO (g) → 2Fe (s) + 3CO2 (g)
Which compound contains two different elements with the same oxidation number?
Choose your answer
Mg(OH)2
Na2SO4
HClO
NH4Cl
When solid sodium iodide and concentrated sulfuric acid react, one of the reactions that takes place is shown below.
8NaI (s) + 9H2SO4 (l) → 8NaHSO4 (s) + 4I2 (g) + H2S (g) + 4H2O (l)
Which species is oxidised in this reaction?
Choose your answer
I-
SO42-
Na+
H+
The following reaction can be used to determine the mass of titanium dioxide in an ore.
3TiO2 (s) + 4BrF3 (l) → 3TiF4 (s) + 2Br2 (l) + 3O2 (g)
Which element increases in oxidation number in this reaction?
Choose your answer
Bromine
Fluorine
Oxygen
Titanium
Which equation shows hydrogen acting as an oxidising agent?
Choose your answer
2Na (s) + H2 (g) → 2NaH (s)
N2 (g) + 3H2 (g) ⇌ 2NH3 (g)
H2 (g) + Cl2 (g) → 2HCl (g)
C2H4 (g) + H2 (g) → C2H6 (g)
Chlorine gas reacts with both hot and cold aqueous sodium hydroxide, each resulting in a different set of products.
Which row gives the oxidation numbers of chlorine in the products of these reactions?
| Hot aqueous sodium hydroxide | Cold aqueous sodium hydroxide | |
|---|---|---|
| A | −1 and +5 | −1 and +1 |
| B | −1 and +5 | −1 and +2 |
| C | +1 and +6 | −1 and +1 |
| D | +1 and +6 | −1 and +2 |
Choose your answer
When solid potassium halides are added to concentrated sulfuric acid, the following reactions take place:
| Reaction 1 | 2KBr (s) + 2H2SO4 (l) → K2SO4 (s) + SO2 (g) + Br2 (l) + 2H2O (l) |
|---|---|
| Reaction 2 | 8KI (s) + 5H2SO4 (l) → 4K2SO4 (s) + H2S (g) + 4I2 (s) + 4H2O (l) |
| Reaction 3 | 2KCl (s) + H2SO4 (l) → K2SO4 (s) + 2HCl (g) |
Which row shows the greatest change in the oxidation number of sulfur for each reaction?
| Reaction 1 | Reaction 2 | Reaction 3 | |
|---|---|---|---|
| A | 1 | 4 | 1 |
| B | 2 | 4 | 0 |
| C | 2 | 8 | 0 |
| D | 4 | 8 | 1 |
Choose your answer
The table shows various ions containing manganese and chlorine.
Which row shows identical oxidation numbers for the central atoms of both ions?
| manganese-containing ion | chlorine-containing ion | oxidation number of central atom | |
|---|---|---|---|
| A | MnO4- | ClO3- | +7 |
| B | MnO42- | ClO2- | +6 |
| C | MnO4- | ClO3- | +5 |
| D | MnO4- | ClO4- | +7 |
Choose your answer
When heated, ammonium nitrate, NH4NO3, can decompose explosively.
NH4NO3 (s) → N2O (g) + 2H2O (g)
The nitrogen atoms in NH4NO3 have different oxidation numbers.
What are the changes in the oxidation numbers as the reaction proceeds?
Choose your answer
+4 and −4
−2 and −4
+4 and −6
+2 and +6
The acid HIO disproportionates when in aqueous solution. This is shown in the equation, where q, r, s and t are simple whole numbers in their lowest ratios.
q HIO (aq) → r I2 (aq) + s HIO3 (aq) + t H2O (l)
Which row gives the values for r and s?
| r | s | |
|---|---|---|
| A | 4 | 2 |
| B | 4 | 1 |
| C | 2 | 1 |
| D | 1 | 2 |
Choose your answer
In winemaking, to prevent oxidation of ethanol by air, sulfur dioxide (SO2) is added. In order to calculate the amount of SO2, a sample is titrated with iodine (I2).
What is the change in the oxidation number of sulfur in this reaction?
Choose your answer
+2 to +6
+4 to +6
+2 to +4
+4 to +5
The table shows the standard electrode potentials of a number of species.
| half-equation | E° / V |
|---|---|
| V3+ (aq) + e− ⇌ V2+ (aq) | −0.26 |
| VO2+ (aq) + 2H+ (aq) + e− ⇌ V3+ (aq) + H2O (l) | +0.34 |
| S4O62− (aq) + 2e− ⇌ 2S2O32− (aq) | +0.09 |
| VO2+ (aq) + 2H+ (aq) + e− ⇌ VO2+ (aq) + H2O (l) | +1.00 |
Which of the following is the lowest possible oxidation number that vanadium(V) can be reduced to by thiosulfate ions?
Choose your answer
+2
+3
+4
+5
The oxidation number of chlorine can range from −1 to +7 in its compounds.
Which reagents and conditions allow elemental chlorine to produce a compound containing chlorine in the +5 oxidation state?
Choose your answer
Concentrated H2SO4 at room temperature.
AgNO3 (aq) followed by NH3 (aq) at room temperature.
Cold dilute NaOH (aq).
Hot concentrated NaOH (aq).
Solid sodium chloride and solid sodium iodide were each added separately to concentrated phosphoric acid and concentrated sulfuric acid. The results are shown in the table below.
| sodium chloride | sodium iodide | |
|---|---|---|
| concentrated H3PO4 | colourless acidic gas formed | colourless acidic gas formed |
| concentrated H2SO4 | colourless acidic gas formed | purple vapour formed |
Which deduction can be made from these observations?
Choose your answer
Concentrated sulfuric acid is a stronger oxidising agent than chlorine.
Concentrated sulfuric acid is a stronger oxidising agent than iodine.
Concentrated phosphoric acid is a stronger oxidising agent than iodine.
Concentrated phosphoric acid is a stronger oxidising agent than concentrated sulfuric acid.
If a solution contains both bromine and chlorine, BrO3– ions are produced.
The reactions leading to the production of BrO3– ions are shown below:
Reaction 1: Br2 + H2O → HBr + HBrO
Reaction 2: 3HBrO + Cl2 → 2Cl– + BrO3– + Br2 + 3H+
Which statement about these reactions is correct?
Choose your answer
In reaction 1, bromine is reduced only.
In reaction 2, chlorine is oxidised.
In reaction 2, bromine is oxidised only.
In both reactions, bromine undergoes disproportionation.
A dilute acid is added to an aqueous solution containing nitrite ions, NO2–, and two different nitrogen compounds are released as gases.
2H+ (aq) + 2NO2– (aq) → H2O (l) + NO (g) + NO2 (g)
Which statement about this reaction is correct?
Choose your answer
The H+ ion is oxidised in this reaction.
Nitrogen is only reduced in this reaction.
The H+ ion acts as a catalyst in this reaction.
Some nitrogen atoms are oxidised and some are reduced in this reaction.
The following reactions are carried out:
Reaction 1: CH3COCH3 + Tollens' reagent
Reaction 2: CH3CH2CHO + Fehling's reagent
Reaction 3: C2H4 + Br2
Which statement about these reactions is correct?
Choose your answer
Propanone undergoes oxidation when it reacts with Tollens' reagent.
Fehling's solution is reduced when it reacts with propanal.
Bromine is oxidised when it reacts with ethene.
Only reaction 2 involves a change in oxidation number.
Which statement describes how concentrated sulfuric acid behaves when it reacts with solid sodium chloride?
Choose your answer
as a reducing agent only
as an oxidising agent only
as an acid only
as an acid and an oxidising agent