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 Protocatechuic Acid
Chemical formula: C7H6O4
Also known as: PCA, Protocatechuate
Protocatechuic Acid is Acidic
At concentration of 1 mM, it has a pH of 3.78
At concentration of 10 mM, it has a pH of 3.25
At concentration of 100 mM, it has a pH of 2.74