Subject: Application of Aqueous Equilibria

I had some trouble with this one problem because it is more wordy then 
most problems we are used to doing and i don't know where to start:We are 
asked to find the molar mass of the acid and the calculated value for the 
second dissociation constant for the acid given the following information. 
A 225- mg sample of a diprotic acid is dissolved in enough water to make 
250 ml of solution.  The pH of this solution is 2.06. A saturated solution 
of calcium hydroxide (Ksp=5.5*10^-6) is prepared by adding excess calcium 
hydroxide to pure water and then removing the undissolved solid by 
filtration. Enough of the calcium hydroxide solution is added to the 
solution of the acid to reach the second equivalence point(as determined 
by a pH meter) is 7.96.  The first dissotiation constant for the acid is 
5.90 * 10^-2.  Assume that the volumes of the solution are additive, all 
solutions are at 25 degrees C and that Ka1 is at least 1000 times greater 
than Ka2.  
If you could help me through the steps i would really appreciate it.  We 
have a test on it and i would really like to understand it

Re: Application of Aqueous Equilibria