JEE CHEMISTRY MCQ: 14 TH GROUP ELEMENTS (P-BLOCK)

Option B ($CaS{O_4}.0.5{H_2}O$) is correct because when gypsum ($CaS{O_4}.2{H_2}O$) is heated to 393 K, it loses water molecules to form plaster of Paris ($CaS{O_4}.0.5{H_2}O$).