Arrange the following ions in order of their condutances in aqueous solution : `Rb^(+), Na^(+),Li^(+)`

Explanation

All the given ions have the same charge but different sizes As a result , each ion possesses a different charge density (charge/ionic volume ) . Since sizes of the given ions follow the order : `Li^(+) lt Na^(+) lt K^(+) lt Rb^(+)` . In aqueous solution, an ion with high charge density gets hydrated ta a greater extent of hydration of `Li^(+)` ion is the highest and that of `Rb^(+)` ion is the lowest . As a result , the effective size of `Rb^(+)` ion will be the largest and that of `Li^(+)` ion will be the smallest . Therefore , effective sizes of the given ions in aqueous solution follow the order : `Li^(+) gt Na^(+) gt K^(+) gt Rb^(+)` . With increase in effective size , the velocity of an ion is directly proportional to the velocity of the ion , values of conductances of the given ions will follow the order : `Li^(+) lt Na^(+) lt K^(+) lt Rb^(+)`