Question

modeling effects of pollutants
you have gone into the field to take water samples from two lakes in your town.
you note the following observations:

• lake a contained many fish swimming in its waters.
• lake b had very few fish swimming in its waters, and a few dead fish floating on the water.

you return to your lab and take ph readings for each sample.
think about how acids and bases would affect the water quality in the two lakes.
which set of ph data would you expect to see based on your observations?

• lake a: ph = 4.5; lake b: ph = 7.5
• lake a: ph = 8.3; lake b: ph = 3.7
• lake a: ph = 6.6; lake b: ph = 6.8
• lake a: ph = 10.2; lake b: ph = 1.7

Explanation:

Fish require a relatively neutral to slightly alkaline pH range (typically 6.5-8.5) to survive. Lake A has many living fish, so its pH should fall in this healthy range. Lake B has few living fish and dead fish, indicating water that is too acidic (far below the healthy range) which is toxic to fish. Among the options, only this set matches: Lake A has a survivable pH, while Lake B has an overly acidic, lethal pH.

Answer:

Lake A: pH = 8.3; Lake B: pH = 3.7