question_answer

Which compound from each of the following pairs is more covalent and why? (a) CuO or CuS (b) \[AgCl\] or \[AgI\] (c) \[PbC{{l}_{2}}\] or \[PbC{{l}_{4}}\] (d) \[BeC{{l}_{2}}\] or \[MgC{{l}_{2}}\]

Answer:

                This is explained with the help of Fazan's rules (a) CuS is more covalent than CuO because \[{{S}^{2-}}\] ion is more polarised than the \[{{O}^{2-}}\] ion due to bigger size. (b) \[AgI\] is more covalent than\[AgCl\]  because\[{{I}^{-}}\] ion is more polarised than\[C{{l}^{-}}\] ion due to bigger size. (c)\[PbC{{l}_{4}}\] is more covalent than \[PbC{{l}_{2}}\] because \[P{{b}^{4+}}\] ion due to smaller size and greater magnitude of positive charge is more polarising than \[P{{b}^{2+}}\]ion. (d)\[BeC{{l}_{2}}\] is more covalent than \[MgC{{l}_{2}}\] because the \[B{{e}^{2+}}\] ion is more polarising than\[M{{g}^{2+}}\] ion due to smaller size.