Titration problem

chanaka89

"S" is a 0.05M aq solution of HCl contatining a salt MCl2. [MCl2] in "S" = 0.05M .For a water soluble base M(OH)2 pKb1=6.0 & pKb2=13.0

1)Initial pH
2)Titration curve for the titration of 25.00ml portion of solution S with 0.1M NaOH

Please tell me how to do the calculations to sketch the curve