A student conducted an experiment where carbon dioxide was bubbled through water - HSC - SSCE Biology - Question 12 - 2009 - Paper 1
Question 12
A student conducted an experiment where carbon dioxide was bubbled through water. The student recorded the pH meter reading every 5 seconds.
| Time (s) | pH meter r... show full transcript
Worked Solution & Example Answer:A student conducted an experiment where carbon dioxide was bubbled through water - HSC - SSCE Biology - Question 12 - 2009 - Paper 1
Step 1
Evaluate the pH readings over time
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Answer
The pH readings decrease from 7.5 to 6.8 over the duration of 20 seconds, indicating that the water is becoming more acidic.
Step 2
Assess the impact of CO₂ on pH
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Answer
As CO₂ is bubbled through water, it reacts to form carbonic acid, which lowers the pH of the solution. This suggests that the increased concentration of CO₂ leads to increased acidity in the water.
Step 3
Choose the best conclusion
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Answer
Based on the data observed, the most valid conclusion is (C) The water became more acidic as the amount of CO₂ in the water increased.
