Answer:
See explanation
Explanation:
The size of the hydration enthalpy of a system depends on the attraction between the ions and the water molecules. Stronger attractions exist between water and smaller ions. The smaller the ion, the higher the hydration enthalpy is.
In the first pair, Na+ is smaller than Cs+ hence Na+ has a larger change in hydration enthalpy.
In the second pair, Sr2+ is smaller than Rb+ hence Sr2+ has a larger change in hydration enthalpy.
In the third pair, Na+ is smaller than Cl- hence Na+ has a larger change in hydration energy.
F- is smaller than O2- hence F- has a larger change in hydration energy.
OH- is smaller than the SH- hence the OH- has a larger change in hydration energy.
