Convert a pH value of 3.7 to [OH-].
pH = -log[H+]
Therefore, [H+] = 10^(-pH)
= 10^(-3.7)
= 2.01 x 10^(-4) M
Since water dissociates into equal parts of [H+] and [OH-], we can calculate [OH-] using the equation Kw = [H+][OH-] and solve for [OH-]:
Kw = 1.0 x 10^(-14)
[OH-] = Kw / [H+]
= (1.0 x 10^(-14)) / (2.01 x 10^(-4))
= 4.98 x 10^(-11) M
Therefore, the concentration of hydroxide ions in a solution with a pH of 3.7 is 4.98 x 10^(-11) M.