A solution has a hydrogen ion (or hydronium ion) concentration of 1.00 * 10-9 M. What is the pH of the solution? 7.5 8.0 9.0 8.5

A solution that has hydrogen ion concentration higher than 10^-7 mol/L is acidic.

A solution that has hydrogen ion concentration lower than this is alkaline.

pH is a measure of ion concentration. Solution with pH less than 7 are acidic, while those with pH higher than 7 are basic or alkaline. Solution with pH 7 are neutral solutions.

In our case, the hydrogen ion concentration is 1x10^-9 M, which is lower than 10^-7, so the solution is alkaline and its pH value is higher than 7.

The pH can be calculated with the formula: pH=-log (H+) = - log (10^-9) = 9