High School

A dark blue beaker labeled 100 milliliters Y has an arrow leading to a pale blue beaker labeled 90 milliliters [tex] H_2O [/tex]. This has an arrow leading to a white beaker labeled 99 milliliters [tex] H_2O [/tex]. The first arrow has a label 10 milliliters over it. The second arrow has a label 1 milliliter over it.

The dark blue beaker has a box below it labeled Beaker number 1 [tex] pH = 2 [/tex]. The pale blue beaker has a box below it labeled Beaker number 2 [tex] pH = ? [/tex]. The white beaker has a box below it labeled Beaker number 3 [tex] pH = ? [/tex].

1. If the [tex] pH [/tex] of Beaker #1 is 2, then what would be the best prediction for the [tex] pH [/tex] of Beaker #2?
2. Since 1 mL of the solution in Beaker #2 is added to 99 mL of water in Beaker #3, what would be the predicted [tex] pH [/tex] of Beaker #3?
3. How many times greater is the concentration of [tex] H^+ [/tex] in Beaker #1 than in Beaker #3?

Answer :

Final answer:

The pH of Beaker #2 after dilution is close to neutral, and the concentration of H+ ions in Beaker #1 is ten times higher than in Beaker #3.

Explanation:

The pH of Beaker #1 is 2, which means it is an acidic solution. As the pH scale is logarithmic, a difference of 1 pH unit represents a ten-fold difference in the concentration of H+ ions. Therefore, Beaker #1 has a concentration of H+ ions that is ten times greater than a solution with a pH of 3.

When 1 mL of the solution in Beaker #2, which has a pH of 2, is added to 99 mL of water in Beaker #3, the resulting solution will have a predicted pH that is close to neutral. This is because the concentration of H+ ions in Beaker #2 is relatively low, and when mixed with a large volume of water, the overall concentration of H+ ions decreases.

In conclusion, the best prediction for the pH of Beaker #2 after the dilution is close to neutral, and the concentration of H+ ions in Beaker #1 is ten times greater than in Beaker #3.