0The pH is a measure of liquid acidity/alkalinity. It ranges from 0 to 14, where 0 is most acidic and 14 is most alkaline. The more acidic, the more hydrogen ions (h+) it contains.
Examples of pH:
Battery acid = 0.3
Lemon juice = 2.2
Vinegar = 2.8
Gastric (stomach) acid = 1.5-3.6
Orange juice = 4.2
Milk = 6.7
Distilled water = 7 (perfectly neutral)
Blood = 7.4 
Sea water = 8
Baking soda = 8.4
Ammonia = 11.5
Bleach = 12.6
