A50.0 ml sample of 1.54×10−2 m naso4 is added to 50.0 ml of 1.28×10−2 ca(no3)2. what percentage of the ca2+ remains unprecipitated? ,

The reaction would be as shown below;
Na2SO4 + Ca(NO3)2 = CaSO4 + 2 NaNO3
The moles of NaSO4 will be;
   = 0.05 × 0.0154 = 0.00077 moles
While the number of moles of Ca(NO3)2
   = 0.05 × 0.0128 = 0.00064 moles
The mole ratio of sodium sulfate and calcium nitrate is 1:1
Ca(NO3)2 is the limiting reactant, so ignoring the Ksp of CaSO4, zero percent of the Ca^2+ ions remain unprecipitated.

B.) falsehope this !