Syllabus Edition
First teaching 2023
First exams 2025
Chlorine is widely used in water treatment plants. Chlorine is reacted with water to produce hydrochloric acid and another chlorine-containing acid.
Which row correctly describes the properties of the reaction?
|
Moles Cl2 used |
Moles HCl produced |
Other product formed |
|
|
A B C D |
1 2 3 4 |
1 3 5 7 |
HClO HClO2 HClO3 HClO4 |
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When chlorine reacts with cold sodium hydroxide the following reaction occurs
Cl2 (aq) + 2NaOH (aq) → NaCl (aq) + NaClO (aq) + H2O (l)
Which of the following statements is correct?
The chlorine has only been oxidised
The oxidation number of Cl in NaClO is 0
The chlorine is simultaneously oxidised and reduced
The oxidation number of Cl in Cl2 is -1
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When chlorine reacts with hot sodium hydroxide the following reaction occurs.
3Cl2 (g) + 6NaOH (aq) → 5NaCl (aq) + NaClO3 (aq) + 3H2O (l)
Which row shows the correct oxidation state of chlorine in each ion?
|
Cl2 |
NaCl |
NaClO3 |
|
|
A B C D |
0 0 0 0 |
-1 +1 +1 -1 |
+5 -5 -3 +3 |
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Chlorine is used to treat drinking water.
Which statement is correct?
Water reacts with chlorine to form hydrochloric acid and chloric(I) acid, HClO
When universal indicator is added to chloric(I) acid, HClO it turns blue then white
Chloric acid does not dissociate further when added to water
Chlorine reacts with cold sodium hydroxide to form sodium chloride and water only
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When chlorine is bubbled through aqueous sodium hydroxide solution different substances are formed depending on the conditions. Which statement is incorrect?
In hot NaOH (aq), ClO3– (aq) ions are formed.
In cold NaOH (aq), ClO– (aq) ions are formed.
The oxidation state of chlorine changes from 0 to +3
Disproportionation of chlorine occurs in both cold and hot aqueous solutions.
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Which statement accurately describes the role of chlorine in the reaction with water?
Chlorine undergoes only oxidation in the reaction, resulting in the formation of ClO– (aq)
Chlorine undergoes only reduction in the reaction, resulting in the formation of Cl– (aq)
Chlorine undergoes both oxidation and reduction in the reaction, forming ClO– (aq) and Cl– (aq)
The oxidation state of chlorine changes from 0 to +5
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A few drops of sodium chlorate (I) solution is added to potassium bromide solution. A red-brown gas is produced along with sodium chloride solution.
Which of the following statements is correct?
The oxidation state of chlorine in NaClO is +5
Chlorine gas is produced
Bromide ions are oxidised in this reaction
NaClO is the reducing agent
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When the yellow liquid NCl3 is stirred into aqueous sodium hydroxide, the reaction that occurs can be represented by the following equation.
2NCl3 (l) + 6NaOH (aq) format('truetype')%3Bfont-weight%3Anormal%3Bfont-style%3Anormal%3B%7D%3C%2Fstyle%3E%3C%2Fdefs%3E%3Ctext%20font-family%3D%22math12bba9f4124283edd644799e0ce%22%20font-size%3D%2216%22%20text-anchor%3D%22middle%22%20x%3D%2210.5%22%20y%3D%2216%22%3E%26%23x2192%3B%3C%2Ftext%3E%3C%2Fsvg%3E)
N2 (g) + 3NaCl (aq) + 3NaClO (aq) + 3H2O (l)
Which of the following is not correct for this reaction?
A bleaching solution remains after the reaction.
Effervescence will be observed.
The nitrogen is oxidised.
The final solution gives a precipitate with acidified silver nitrate.
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Which is the correct equation for the reaction of hot, dilute aqueous sodium hydroxide, NaOH, and chlorine, Cl2?
Cl2 + 2NaOH → NaCl + NaClO + H2O
Cl2 + 2OH- → ClO- + H2O + e-
Cl2 + 6OH- → ClO3- + 3H2O + e-
3Cl2 + 6NaOH → 3NaCl + 3NaClO3 + H2O
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What is the main disinfectant formed when chlorine gas is added to water during purification?
HClO
HCl
ClO2
CHCl3
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