posted by Kate .
What is the [S^-2] in a saturated solution (.1 M) of H2S, in which the pH had been adjusted to 5.00 by the addition of NaOH? For H2S, Ka1= 1.1X10^-7 and Ka2=1.0X10^-14
Those k values don't look right to me but I assume you copied them as is from your worksheet.
(H^+)^2(S^-2)/(H2S) = k1k2
You have only one unknown, the (S^-2). Substitute and solve for that.