The pH of a substance that has an equal number of hydrogen ions (H+) and hydroxide ions (OH–) is 7. This value is considered neutral on the pH scale.
To understand this further, it helps to know how the pH scale works. The pH scale ranges from 0 to 14, where 7 is the midpoint. Values below 7 indicate acidity, characterized by a higher concentration of hydrogen ions, while values above 7 indicate alkalinity, characterized by a higher concentration of hydroxide ions.
When a solution has an equal concentration of H+ and OH–, the two ions neutralize each other, resulting in a neutral solution, which is pure water at 25 degrees Celsius. Therefore, if you were to measure the pH of such a solution, it would consistently show a pH of 7, representing a balanced state without any acidic or basic properties.