Answer:
pOH = 12.538
Step-by-step explanation:
pH = -log[H3O+] = -log(3.45*10^-2) = 1.4622
pOH = 14 - pH = 12.5378, which can be rounded to 12.538 with 3 sig figs (Note: the pOH as 12.538 does not have 5 sig figs, but instead 3 because of the properties of logs.)