Chapter 12, Problem 12.42SP

Interpretation Introduction

Interpretation:

The larger (more negative)hydration energy should be selected from the followings:

(a) Na+ or Cs+
(b) K+ or Ba²+

Concept introduction:

The amount of heat released when new bonds are formed between the ions and the water molecules is called the hydration energy.
One of the factors that govern the hydration energy is the size of the ion.
Smaller ions have stronger attractions and so the hydration energies is higher. With increase in the size of the ion the hydration energy decreases.
As the charge on ion increases, the attractions also increase. And also hydration energy is also higher.