What is hydration?What is its mechanism?What are the factors that it depends on?

Answer 1

Hydration :
The incorporation of molecular water into a complex with the molecules or units of another species. The complex may be held together by relatively weak forces or may exist as a definite compound. Many salts form solid hydrates when exposed to water vapor under certain conditions of temperature and pressure. Water is lost from these compounds when they are heated or when the water vapor pressure falls below a minimum value. Solids forming hydrates at low pressures are used as drying agents.
In organic chemistry, a hydration reaction is a chemical reaction in which a hydroxyl group (OH-) and a hydrogen cation (an acidic proton) are added to the two carbon atoms bonded together in the carbon-carbon double bond which makes up an alkene functional group. The reaction usually runs in a strong acidic, aqueous solution. Hydration differs from hydrolysis in that hydrolysis cleaves the non-water component in two. Hydration leaves the non-water component intact.

The general chemical formula of the reaction is the following:

RRC=CH2 in H2O/acid → RRC-CH2-OH
In the first step, the acidic proton bonds to the less substituted carbon of the double bond following Markovnikov's rule. In the second step an H2O molecule bonds to the other, more highly substituted carbon. The oxygen atom at this point has three bonds and carries a positive charge. Another water molecule comes along and takes up the extra proton.

When carried out in the laboratory, this reaction tends to yield many undesirable side products and in its simple form described here is not considered very useful for the production of alcohol.

For molecular structure pl. click:
http://en.wikipedia.org/wiki/Hydration_reaction

Answer 2

Hydration is the attaching of H20 to another atom or molecule. In it's simplest form the water just surrounds a molecule/atom. For example when Al3+ is dissolved in water it is surrounded by 6 H20 molecules. It can also be incorporated into a molecule such as CuSO4 . 5H20. In the most complex form it creates a hydration synthesis. For example CH2=CH2 + H20 --> CH3CH3OH.