The pH level is the measure of acidity or alkalinity of a solution. Solutions at a temperature of 25 degrees Celsius with a pH of more then seven mean that they’re basic (alkaline). The most common neutral solution is freshly distilled (filtered) water. When the pH is less then seven at 25 degrees Celsius they are acidic. At a pH of 7.0, they’re known as neutral. If the pH is lower, the solution is more acidic. We researched and found out that pure Hydrochloric acid has a pH level of a bit more then zero so it was the strongest (most acidic) acid. The vinegar has a pH of 3.0 and the lemon juice had a pH of 2.1.