The diagram shows what happens when a small amount of potassium bromide solution, KBr, is added to a solution of chlorine, Cl₂ - OCR Gateway - GCSE Chemistry: Combined Science - Question 18 - 2020 - Paper 10
Question 18
The diagram shows what happens when a small amount of potassium bromide solution, KBr, is added to a solution of chlorine, Cl₂.
(a) Write the balanced symbol equati... show full transcript
Worked Solution & Example Answer:The diagram shows what happens when a small amount of potassium bromide solution, KBr, is added to a solution of chlorine, Cl₂ - OCR Gateway - GCSE Chemistry: Combined Science - Question 18 - 2020 - Paper 10
Step 1
Write the balanced symbol equation for the reaction between potassium bromide, KBr, and chlorine, Cl₂.
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Answer
The balanced symbol equation for the reaction is:
2 KBr+Cl2→2KCl+Br2
This shows that two moles of potassium bromide react with one mole of chlorine gas to produce two moles of potassium chloride and one mole of bromine.
Step 2
Write down the name of the chemical which makes the solution orange.
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Answer
The chemical that makes the solution orange is bromine (Br₂). This occurs as bromine is released into the solution during the reaction.
Step 3
Write the half equation for the formation of chloride ions, Cl⁻, from chlorine, Cl₂.
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Answer
The half equation for the formation of chloride ions from chlorine is:
Cl2+2e−→2Cl−
This equation illustrates that chlorine gas gains two electrons to form two chloride ions.
Step 4
In this reaction is chlorine oxidised or reduced? Explain your answer.
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Answer
Chlorine is reduced in this reaction. This is because it gains electrons (as shown in the half equation) which decreases its oxidation state, indicating a reduction process.
Step 5
Explain why chlorine is more reactive than bromine.
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Answer
Chlorine is more reactive than bromine due to its higher electronegativity and smaller atomic radius. Chlorine can attract electrons more easily, facilitating quicker and more effective reactions, particularly with halides like potassium bromide.
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