To compare the acidity of different solutions, chemists use the pH (which is a single number, not the product of p and H). The pH is defined in terms of the concentration, x, of hydrogen ions in the solution as
![316_adfcc1a5-e6e1-4580-ba39-90fd9329a92b.png](https://secure.tutorsglobe.com/CMSImages/316_adfcc1a5-e6e1-4580-ba39-90fd9329a92b.png)
Find the rate of change of pH with respect to hydrogen ion concentration when the pH is 2.