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7. (a) Describe what is seen when chlorine water is added to potassium bromide solution and the mixture shaken - Edexcel - GCSE Chemistry - Question 7 - 2018 - Paper 1
Question 7
7. (a) Describe what is seen when chlorine water is added to potassium bromide solution and the mixture shaken. (b) Chlorine reacts with potassium bromide to form p... show full transcript
Worked Solution & Example Answer:7. (a) Describe what is seen when chlorine water is added to potassium bromide solution and the mixture shaken - Edexcel - GCSE Chemistry - Question 7 - 2018 - Paper 1
Step 1
Describe what is seen when chlorine water is added to potassium bromide solution and the mixture shaken.
Answer
When chlorine water is added to potassium bromide solution, the solution changes color. Initially, the potassium bromide solution is colorless. Upon the addition of chlorine water and shaking, the mixture turns yellow or brown, indicating the formation of bromine.
Step 2
Explain, using the equation, how you know that chlorine has been reduced.
Answer
Chlorine is reduced because it gains electrons during the reaction. In the equation, Cl2 + 2KBr → 2KCl + Br2, we can see that chlorine (Cl2) is converted into chloride ions (2Cl⁻), which indicates that chlorine gains electrons:
ightarrow 2 ext{Cl}^-$$. This change in oxidation state shows that chlorine has been reduced.Step 3
Step 4
Step 5
Describe a simple experiment to show that charged particles are present in this solution.
Answer
A simple experiment to demonstrate the presence of charged particles in the solution involves using a conductivity tester or a circuit with a battery and electrodes. When the solid ionic compound is dissolved in water, the solution can complete the circuit, allowing a light bulb to light up, showing that charged particles, or ions, are present in the solution.