During hydrate formation from aqueous solution, water can be associated in different forms. Indicate the wrong combination. (i) Coordinated water – [Cr(H₂O)₆]3+ 3Cl– (ii) Interstitial water – BaCl₂.2H₂O (iii) Hydrogen bonded water– [Cu(H₂O)₄]2+ SO₄ 2–. H₂O

In coordinated water, there is a ligand in the metal complex. Here, the metal atom and the water molecules are held by coordinate bonds, as given in (i). The water that is present in the interstitial sites of a crystal lattice is called interstitial water, as given in (ii). If the water is linked through hydrogen bonding with some other ion, then it is hydrogen bonded water, as in (iii). So, all of them are correct combinations.