Table of Contents
- 1 How does hydration energy affect reduction potential?
- 2 What is the relation between hydration energy and ionisation energy?
- 3 How is hydration enthalpy related to oxidising agent?
- 4 How does having waters of hydration affect the enthalpy for dissolving?
- 5 Is hydration energy endothermic or exothermic?
- 6 How does high hydration enthalpy of fluorine make it a good oxidising agent?
How does hydration energy affect reduction potential?
In solution, the cation is stabilized by hydration (the cation is surrounded or protected by a layer of water molecules around it). The more stable the cation, more easily does the atom lose electron. Therefore higher the hydration energy, higher the reduction potential.
How is hydration energy related to reducing agent?
As Lithium is smaller in size, it has high ionization energy. Thus, Li has greater tendency to lose electrons in solution than other alkali metals. Hence, Li is the strongest reducing agent. Thus, the reason for large reducing power of Li is due to it’s high Hydration Energy.
What is the relation between hydration energy and ionisation energy?
lower the ionisation energy and higher the hydration energy, more is the reducing character of the atom because for lower ionisation energy more easier the electrons can be ejected and given to the other species(which is going to be reduced and calld oxidising agent).
What happens when hydration energy increases?
The reason why the latter happens is that the hydration energy does not completely overcome the lattice energy and the remainder has to be taken from the water to compensate for the energy loss….Hydration Enthalpy of Elements.
| Ion | ꕔHHyd |
|---|---|
| K+ | -321 |
| Rb+ | -300 |
| Cs+ | -277 |
| F- | -506 |
The magnitude of hydration enthalpy depends on the charge density of the ions. The higher the charge density greater will be the oxidizing power ( or strength of oxidising agent) and also the higher will be hydration enthalpy.
Is hydration enthalpy and ionisation enthalpy are same?
The charge density is more for smaller ions and hence the smaller ions have higher values of hydration enthalpy. The higher the charge density the higher will be the force of attraction between the ion and the water polar end….Hydration Enthalpy of Elements.
| Ion | ꕔHHyd |
|---|---|
| I- | -296 |
How does having waters of hydration affect the enthalpy for dissolving?
The heat energy needed to break up 1 mole of the crystal lattice is the lattice dissociation enthalpy. The hydration enthalpy is the enthalpy change when 1 mole of gaseous ions dissolve in sufficient water to give an infinitely dilute solution. Hydration enthalpies are always negative.
Why hydration enthalpy of alkali metal ions decreases with increase in ionic sizes?
Smaller the ion, higher will be the hydration enthalpy because smaller atoms can accommodate a large number of water molecules around it, and gets highly hydrated. Hydration enthalpy decreases down the group because down the group size of the atom increases because of addition of extra valence shells.
Is hydration energy endothermic or exothermic?
Hydration involve forces of attraction between water and given particle. Formation of bond always result in evolution of energy . That is why it is exothermic. Enthalpy of hydration is exothermic for ions dissolving in water because ions form strong ion-dipole attractions with water.
What happens when hydration energy is less than lattice energy?
If the hydration energy is equal to or greater than the lattice energy, then the salt is water-soluble. In salts for which the hydration energy is higher than the lattice energy, solvation occurs with a release of energy in the form of heat.
How does high hydration enthalpy of fluorine make it a good oxidising agent?
The oxidising capability of a substance depends upon three factors: bond dissociation enthalpy, electron gain enthalpy and hydration energy. low enthalpy of dissociation of F-F bond (158.8/ kJ mol-1). Due to its small size Fluorine’s hydration energy is very high hence better the oxidizing power.