A mixture of 100 m mol of $$Ca(OH)_2$$ and 2 g of sodium sulphate was dissolved in water and the volume was made up to 100 mL. What is the mass of calcium sulphate formed and the concentration of $$OH^-$$ in resulting solution, respectively? (Molar mass of $$Ca(OH)_2$$, $$Na_2SO_4$$ and $$CaSO_4$$ are 74, 143 and 136 g mol$$^{-1}$$, respectively; $$K_{sp}$$ of $$Ca(OH)_2$$ is $$5.5 \times 10^{-6}$$)