How much greater is the alkalinity of a brine with a pH of 10 compared to one with a pH of 8?

The correct answer is based on the concept of the pH scale, which is logarithmic. Each whole number change on the pH scale represents a tenfold change in acidity or alkalinity. A pH of 10 indicates a more alkaline solution than a pH of 8.

To calculate the difference in alkalinity, we can look at the difference between the two pH values. The difference is 10 - 8 = 2. Since the scale is logarithmic, each increment of 1 in pH represents a tenfold change. Therefore, a difference of 2 means the alkalinity is 10^2, which equals 100 times greater.

This fundamental understanding of the logarithmic nature of the pH scale underpins the reason for the selection of the correct answer. The magnitude of the increase in alkalinity from a pH of 8 to a pH of 10 is significant, and thus the alkalinity at pH 10 is indeed 100 times greater than that at pH 8.