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This question is about sodium chloride - AQA - GCSE Chemistry - Question 6 - 2017 - Paper 1
Question 6
This question is about sodium chloride. A student reacted hydrochloric acid and sodium hydroxide solution to produce sodium chloride solution. The student: - meas... show full transcript
Worked Solution & Example Answer:This question is about sodium chloride - AQA - GCSE Chemistry - Question 6 - 2017 - Paper 1
Step 1
The hydrochloric acid and sodium hydroxide solution were the same concentration. Suggest one reason why the temperature change could be greater than expected.
Answer
The correct choice is the initial temperature reading was too low. If the initial temperature of the hydrochloric acid was not recorded accurately, the calculated temperature change would be greater than it should be, indicating a larger temperature change.
Step 2
What conclusion can you make about the reaction from the results in Table 2?
Answer
The results indicate that the reaction is exothermic. In all three experiments, the highest temperature reached is greater than the initial temperature of the hydrochloric acid, confirming that heat is released during the reaction.
Step 3
Explain what happens at the negative electrode and why sodium is not produced.
Answer
At the negative electrode, positive hydrogen ions gain electrons to form hydrogen gas. Sodium ions cannot be reduced as sodium is highly reactive and remains in solution. Instead, hydrogen is displaced due to its lower reactivity compared to sodium, hence no sodium production occurs.
Step 4
Step 5