A mass of 0.100 mg TIOH is mixed with 174 ml of pure water. Calculate the pH of this aqueous solution?

TlOH is a strong base just like NaOH; therefore, (OH^-) = (TlOH)

pOH = -log(OH^-), then
pH + pOH = pKw = 14.
You pOH and pKw, solve for pH.