A solution at pH 6 contains _________ H+ than the same amount of a solution at pH 8.
a. 20 times more
b. 100 times more
c. 2 times less
d. 100 times less

Verified step by step guidance

1. Understand the concept of pH: pH is a measure of the hydrogen ion concentration (H⁺) in a solution. It is calculated using the formula: $pH=-{\log }^{(}\mathrm{[H⁺]})$. A lower pH indicates a higher concentration of H⁺ ions.
2. Recognize the relationship between pH values: Each unit change in pH represents a tenfold difference in H⁺ concentration. For example, a solution with pH 6 has 10 times more H⁺ ions than a solution with pH 7.
3. Compare the pH values given in the problem: The solution at pH 6 is being compared to the solution at pH 8. The difference in pH is 2 units (8 - 6 = 2).
4. Calculate the difference in H⁺ concentration: Since each pH unit represents a tenfold change, a difference of 2 pH units means the H⁺ concentration changes by a factor of ${10}^2$, which equals 100.
5. Interpret the result: A solution at pH 6 contains 100 times more H⁺ ions than the same amount of a solution at pH 8. This corresponds to option b in the problem.

Key Concepts

pH Scale

The pH scale measures the acidity or alkalinity of a solution, ranging from 0 to 14. A pH of 7 is neutral, while values below 7 indicate acidity and above 7 indicate alkalinity. Each whole number change on the pH scale represents a tenfold change in hydrogen ion concentration (H+), meaning that a solution with a pH of 6 is ten times more acidic than one with a pH of 7.

Hydrogen Ion Concentration

Hydrogen ion concentration refers to the amount of H+ ions present in a solution. It is crucial for determining the pH level; as the concentration of H+ increases, the pH decreases. For example, a solution at pH 6 has a higher concentration of H+ ions compared to a solution at pH 8, which is less acidic and has fewer H+ ions.

Logarithmic Scale

The pH scale is logarithmic, meaning that each unit change in pH corresponds to a tenfold change in H+ concentration. Therefore, a solution with a pH of 6 has 100 times more H+ ions than a solution with a pH of 8. This logarithmic relationship is essential for understanding how small changes in pH can significantly affect acidity.