Question

The sequence of ionic mobilty in the aqueous solution is
A. `K^(+) gt Na^(+) gt Rb^(+) gt Cs^(+)`
B. `Cs^(+) gt Rb^(+) gt K^(+) gt Na^(+)`
C. `Rb^(+) gt K^(+)gt Cs^(+) gt Na^(+)`
D. `Na^(+) gt K^(+) gt Rb^(+ gt Cs^(+ )`

Answer 1

Correct Answer - B
Smaller the size of an ion, more strongly it is hydrated and less is the ionic mobility. The sizes of the unhydrated ions increase in the order:
`Na^(+) lt K^(+) lt Rb^(+) lt Cs^(+)`
The sizes of the hydrated ions will be in the order:
`Cs^(+) lt Rb^(+) lt K^(+) lt Na^(+) `
Hence, their ionic mobilities will be in the order:
`Cs^(2+) gt Rb^(+) gt K^(+) gt Na^(+)`