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 DL-tartaric Acid
Chemical formula: C4H6O6
Also known as: racemic acid
DL-tartaric Acid is Acidic
At concentration of 1 mM, it has a pH of 3.19
At concentration of 10 mM, it has a pH of 2.58
At concentration of 100 mM, it has a pH of 2.03