NEET2008Chemistrys Block ElementsActual
The sequence of ionic mobility in aqueous solution is
Options
- AK ⁺> Na ⁺> Rb ⁺> Cs ⁺
- BCs ⁺> Rb ⁺> K ⁺> Na ⁺
- CRb ⁺> K ⁺> Cs ⁺> Na ⁺
- DNa ⁺> K ⁺> Rb ⁺> Cs ⁺
Correct answer
B. Cs ⁺> Rb ⁺> K ⁺> Na ⁺
Step-by-step solution
Key Idea: The smaller the size of ion, the greater the degree of hydration and Mobility of ion in aqueous solution 1 size of ion in aqueous solution Generally in a group size or radii of ions increases, so Li has smallest size thus bind maximum number of water molecules with itself and becomes largest in size (in aqueous solution). Hence, the order of ionic radii (size) of alkali metal ions in aqueous solution is Li ⁺> Na ⁺> K ⁺> Rb ⁺> Cs ⁺ Thus, the order of mobility Cs ⁺> Rb ⁺> K ⁺> Na ⁺> Li ⁺