Titration of a 100.0 ml solution of certain weak acid and a strong base resulted in the below titration curve that asymptotically tends towards 12.0 at infinite strong base volumes. Using the curve, estimate
a) The concentration of the strong base.
b) Ka of the weak acid.
c) The concentration of the weak acid solution.
d) Sketch, on the same plot, values of α0 and α1s.    

12 11 10 9 8 7 6 5 4 3 2 -5 25 50 75 100 125 150 175 200 225 250 275 ml Strong Base added 300 325 350 375 400 425 450 ****** 475 500