A sample of river water taken from point X is analysed - HSC - SSCE Chemistry - Question 15 - 2015 - Paper 1
Question 15
A sample of river water taken from point X is analysed.
Which row of the table shows the most likely results?
| Turbidity (NTU) | BOD (ppm) | pH | Total dissolved ... show full transcript
Worked Solution & Example Answer:A sample of river water taken from point X is analysed - HSC - SSCE Chemistry - Question 15 - 2015 - Paper 1
Step 1
Analyze water quality parameters
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Answer
Given the location of point X near farmland and the river, we can expect higher turbidity and BOD due to runoff. Factors such as land use and potential pollutants must be considered in our analysis.
Step 2
Consider turbidity
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Answer
The turbidity level is a crucial indicator. Row A shows a turbidity of 400 NTU, which is consistent with high levels of pollution due to agricultural runoff. Lower values in rows B and D suggest lesser pollution which is unlikely for a site near farmland.
Step 3
Examine BOD and pH levels
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Answer
A high BOD of 18 ppm in row A indicates significant organic material, while the pH of 6.5 falls within the typical range for freshwater bodies. This supports the selection of row A as indicative of polluted water.
Step 4
Identify total dissolved solids (TDS)
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Row A's total dissolved solids count of 22,000 ppm is realistic for water impacted by agricultural runoff, confirming the presence of dissolved nutrients and pollutants.
Step 5
Conclusion
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Answer
Based on these analyses, the most likely results for point X are found in row A, indicating elevated levels of turbidity, BOD, and total dissolved solids, consistent with pollution near farmland.
