Question

How does the pH of acid change when a base is added?

Answer 1

The $pH$ of water indicates how acidic or basic it is. The scale runs from 0 to 14, with 7 representing neutral. A $pH$ less than 7 indicates acidity, while a $pH$ greater than 7 indicates baseness. The $pH$ of water is actually a measure of the relative amount of free hydrogen and hydroxyl ions.

Complete answer:
The $pH$ of a solution is a measure of its acid concentration. (This is measured in negative logs.) $pH$ ranges from 0 to 6.9. Increasing the acid concentration lowers the $pH$ by increasing the concentration of hydrogen ions. The $pH$ is 7.1-14. Increasing the base concentration raises the concentration of hydroxide ions while decreasing the concentration of hydrogen ions.
The concentration of ${{H}_{3}}{{O}^{+}}$ ions in a solution is measured by $pH$ . The addition of an acid raises the concentration of ${{H}_{3}}{{O}^{+}}$ ions in the solution. When an acid is added to a basic solution, it becomes less basic and moves closer to the middle of the pH scale. This is known as neutralizing the base.
By definition, $pH=-lo{{g}_{10}}[{{H}_{3}}{{O}^{+}}]...$
And thus when a base is added to acid solution… ${{H}_{3}}{{O}^{+}}$ DECREASES
${{H}_{3}}{{O}^{+}}+H{{O}^{-}}\to {{H}_{2}}O$.

Note:
When an alkali is added to an acid, a chemical reaction occurs, resulting in the formation of a new substance. If you combine the correct amounts of acid and alkali, you will get a neutral solution. Antacids, for example, contain alkalis, which help to increase the $pH$ and restore the proper balance.