JEE Advanced Model Paper 9 with solutions for online practice

The degree of hardness of a sample of hard water is 500ppm. The hardness is due toonly calcium chloride. The minimum concentration (in moles/lit) of sodium sulphatewhich must be added for removing the Ca2+ ions from this water sample is
(y × 1.2 × 10−3) . The value of 'y' is [Ksp of CaSO4 = 2.4 × 10−5]