This question is about sodium halides - AQA - A-Level Chemistry - Question 9 - 2020 - Paper 1
Question 9
This question is about sodium halides.
1. State what is observed when silver nitrate solution is added to sodium fluoride solution.
2. State one observation when s... show full transcript
Worked Solution & Example Answer:This question is about sodium halides - AQA - A-Level Chemistry - Question 9 - 2020 - Paper 1
Step 1
State what is observed when silver nitrate solution is added to sodium fluoride solution.
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Answer
The solution remains colourless, indicating no visible change.
Step 2
State one observation when solid sodium chloride reacts with concentrated sulfuric acid.
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Answer
Observation: The reaction produces misty or steamy fumes of hydrogen chloride gas.
Equation:
NaCl (s)+H2SO4(l)→NaHSO4(s)+HCl (g)
Role: The chloride ions (Cl⁻) act as a base or proton acceptor during the reaction.
Step 3
Give an equation for the redox reaction between solid sodium bromide and concentrated sulfuric acid. Explain, using oxidation states, why this is a redox reaction.
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Explanation: In the reaction, the bromine (Br) changes oxidation state from -1 to 0, indicating that bromide (Br⁻) is oxidized to bromine (Br₂). Meanwhile, sulfur (S) in sulfuric acid reduces, demonstrating that a redox reaction has occurred.
Step 4
State what is observed when aqueous chlorine is added to sodium bromide solution.
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Answer
Observation: A yellow or orange solution is formed.
