A solution with a pH value of 0 is extremely acidic. A solution with a pH value of 14 is extremely basic. A neutral solution, such as pure water, is neither acidic nor basic and has a pH of 7. Common solution have a wide range of acidity. Milk, for example, has a pH of 6.5, meaning that it is only slightly acidic. On the other hand, natural acids found in the stomach are highly acidic, with pH values between 1.0 and 2.0
In addition to their pH levels, acids may be further classified as organic or inorganic