Answer:
The water in the stream is acidic since the pH of the water is 6.4, and numbers under 7.0 on the pH scale is considered acidic. And because it is more acidic, it obviously has more hydronium ions than hydroxide ions. But if we wanted to make sure, [H3O+] = 10^-6.4 which equals a 3.98 x 10^-7 molar concentration of hydronium while [OH-] = 10^-7.6 which equals 2.51 x 10^ -8 molar concentration of hydroxide. And since 3.98 x 10^-7 is greater than 2.51 x 10^-8, there are more hydronium ions than hydroxide ions.
