An octahedral complex of chromium(III) has the empirical formula CrCl ₃ 6 H ₂ O . When 0.1 moles of this complex is dissolved in water and treated with an excess of AgNO ₃ solution, 28.7 g of AgCl precipitate is formed. The number of water molecules present inside the coordination sphere of the complex is (Given: Atomic masses of Ag = 108 u , Cl = 35.5 u )

Step-by-step solution

Molar mass of AgCl = 108 + 35.5 = 143.5 g/mol . Moles of AgCl precipitated = 28.7 143.5 = 0.2 moles . Since 0.1 moles of the complex yields 0.2 moles of AgCl , 1 mole of the complex will yield 2 moles of AgCl . This indicates that there are 2 ionizable chloride ions present outside the coordination sphere. Out of the 3 chlorine atoms in the empirical formula, 1 must be present inside the coordination sphere. Since chromium(III) forms octahedral complexes, its coordination number is 6 . To satisfy the coordination n