How much more acidic is a pH of 9 compared to a pH of 7?

A pH scale measures how acidic or basic a solution is, where lower numbers indicate higher acidity and higher numbers indicate greater alkalinity. Each whole number change on the pH scale represents a tenfold change in acidity or alkalinity.

When comparing a pH of 9 to a pH of 7, you are looking at a difference of 2 units on the scale. To calculate how much more alkaline (or less acidic) a pH of 9 is compared to a pH of 7, you look at the change between the two pH levels.

Since a pH difference of 1 corresponds to a factor of 10, a difference of 2 units means you would multiply 10 (from the change from 7 to 8) by another 10 (the change from 8 to 9). Therefore, moving from a pH of 7 to a pH of 9 is equivalent to being 10 multiplied by 10, resulting in a factor of 100.

Thus, a pH of 9 is 100 times less acidic than a pH of 7. Understanding these calculations emphasizes the logarithmic nature of the pH scale and helps in grasping the exponential relationship