I. The correct formula for Calgon is Na6(PO3)6 is a correct statement. II. Exhausted permutit is regenerated by aqueous KCl solution. It is an incorrect statement. The exhausted permutit is regenerated by brine solution, i.e. aqueous NaCl. III. Calcium stearate is soluble in water is an incorrect statement. Calcium stearate being a carboxylate salt of Ca is highly insoluble in water but is soluble in pyridine. IV. In ice crystal, each oxygen is surrounded by four oxygen atoms. Each water molecule is hydrogen bonded to 4 other neighbouring water molecules. The statement is correct. ∴ I and IV only are correct.
