IIT JEE , AIEEE Forum - Chemistry , Physical Chemistry

rohitkuruvila

can someone please explain the concept of hydration energy and hydration rings.why does NaCl have more hydration rings than glucose.

deovrat

The energy change accompanying the hydration of a mole of gase and ions is called hydration energy.

deovrat

and what do u want??

rooney

Guys...is hydration rings in syllabus ?

ps - never came across this term

(62)

it is

apurviitjee2008

PLz look at this for Hydration energy

Enthalpy of hydration, of an ion is the amount of energy released when a mole of the ion dissolves in a large amount of water forming an infinite dilute solution in the process,
Mz+(g) + mH2O ® Mz+(aq)
where Mz+(aq) represents ions surrounded by water molecules and dispersed in the solution. The approximate hydration energies of some typical ions are listed here. The table illustrates the point that as the atomic numbers increases, so do the ionic size, leading to a decrease in absolute values of enthalpy of hydration.

as for Hydration rings ...
me too hearing it for first time will try to answer later.

rooney

To think about it , I will share my understanding of Hydration energy.

When an ionic compound like NaCl is added to water, it breaks down into its constituent ions. The ions get sorrounded by water molecules and interact with them forming bonds. Now, a water molecule has Hydrogen and Oxygen atoms. So, a Na+ ion will form a bond with the Oxygen part of the water molecules. Now, whenever a bond is formed, energy is released. This individual energy released due to bond formation, when added up for all the bonds formed by 6 x 10^23 ions is called hydrations energy. Thus as , atomic no. increases, ionic size increases, bond length increases, bond strength decreases and thus, less energy is released on bond formation. Thus, as atomic no. of ions increases, hydration energy decreases. So, Li+ has max hydration energy.

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