This little website shows you the pH of various acids, bases, food products, bodily fluids, cleaners, and more!
Here's a random substance:
pH of Ascorbic Acid
Chemical formula: C6H8O6
Also known as: vitamin C
Ascorbic Acid is Acidic
At concentration of 1 mM, it has a pH of 3.59
At concentration of 10 mM, it has a pH of 3.04
At concentration of 100 mM, it has a pH of 2.53