A neutral pH level is a value of seven on the pH scale. This number lies at the center of the scale and is the value that is associated with pure water. A pH level below or above seven indicates that the liquid is either an acid or a base.
An example of an acid on the pH scale is vinegar, which is typically assigned a value between two and three. An example of a base is ammonia, which has a pH value between 11 and 12. The scale is logarithmic in nature, which means that any value above or below the neutral pH of seven is ten times more or less acidic.