Answer:
[H+] = 1.58*10^-4, [OH-] = 6.31*10^-11
Step-by-step explanation:
Since we know pH = -log [H+], we can work backwards to find [H+] by doing 10^(-pH) = 10^(-3.8) = 1.58*10^-4. Now you have half of your answer. To find [OH-], you can use the relationship: [H+] * [OH] = 10^-14, so [OH-] = 10^-14/ 1.58*10^-4 = 6.31*10^-11.
Hope this helps!