JEE Main202117 Mar 2021Morning ShiftChemistrys Block ElementsActual
The correct order of conductivity of ions in water is:
Options
- ANa + > K + > Rb + > Cs +
- BCs + > Rb + > K + > Na +
- CK + > Na + > Cs + > Rb +
- DRb + > Na + > K + > Li +
Correct answer
B. Cs + > Rb + > K + > Na +
Step-by-step solution
→ Li + Na + K + Rb + Cs + Hydration energy ↑ As the size of gaseous ion decreases, it gets more hydrated in water and hence, the size of aqueous ion increases. When this bulky ion move in solution, it experience greater resistance and hence lower conductivity. Size of gaseous ion: Cs + > Rb + > K + > Na + Size of aqueous ion: Cs + < Rb + < K + < Na + Conductivity: Cs + > Rb + > K + > Na +