Which solution among the given options has the lowest pH value and therefore the greatest number of hydrogen ions?

Which solution among the given options has the lowest pH value and therefore the greatest number of hydrogen ions?

• A. A = 2.5
• B. B = 3.7
• C. C = 7.1
• D. D = 9.0

Answer: (A)

The solution with the lowest pH value indicates a higher concentration of hydrogen ions (H⁺) in that solution. pH is a logarithmic scale, where each whole number change on the scale represents a tenfold change in acidity or hydrogen ion concentration. This means that as the pH value decreases, the concentration of hydrogen ions increases. In this case, the solution with a pH of 2.5 has the lowest pH compared to the other solutions listed. A pH of 2.5 is significantly more acidic than the others, meaning it has a greater number of hydrogen ions present in that solution. A pH of 3.7 is still acidic, but not as much as 2.5. pH values like 7.1 are considered neutral (pure water), and a pH of 9.0 is basic, indicating a lower concentration of H⁺ ions. Thus, since a lower pH corresponds directly to a higher hydrogen ion concentration, the solution with a pH of 2.5 is indeed the correct choice for having the greatest number of hydrogen ions.

The solution with the lowest pH value indicates a higher concentration of hydrogen ions (H⁺) in that solution. pH is a logarithmic scale, where each whole number change on the scale represents a tenfold change in acidity or hydrogen ion concentration. This means that as the pH value decreases, the concentration of hydrogen ions increases.

In this case, the solution with a pH of 2.5 has the lowest pH compared to the other solutions listed. A pH of 2.5 is significantly more acidic than the others, meaning it has a greater number of hydrogen ions present in that solution. A pH of 3.7 is still acidic, but not as much as 2.5. pH values like 7.1 are considered neutral (pure water), and a pH of 9.0 is basic, indicating a lower concentration of H⁺ ions.

Thus, since a lower pH corresponds directly to a higher hydrogen ion concentration, the solution with a pH of 2.5 is indeed the correct choice for having the greatest number of hydrogen ions.