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 Crotonic Acid
Chemical formula: C4H6O2
Also known as: 3-butenoic acid, (2E)-But-2-enoic acid, (E)-But-2-enoic acid, (E)-2-Butenoic acid, Crotonic acid, trans-2-Butenoic acid, beta-Methylacrylic acid, 3-Methylacrylic acid
Crotonic Acid is Acidic
At concentration of 1 mM, it has a pH of 3.84
At concentration of 10 mM, it has a pH of 3.32
At concentration of 100 mM, it has a pH of 2.81