Recrystallization
is one of the most important methods available for the purification of solids
Recrystallization
It involves the preparation of a saturated solution of the organic compound in an appropriate solvent at an elevated temperature and filtering this solution while hot.
Insoluble impurities
are removed during hot filtration
animal charcoal
Colored impurities present in most organic substances may be removed by the addition of
fluted filter paper
maximizes the flow rate during gravity filtration
Supersaturated solution
A difficulty often encountered in recrystallization is the failure of the solute to crystallize. This is frequently due to too
extensive inclusion in the cyrstals
rapid cooling causes
Seeding
addition of a small crystal of the pure substance to induce crystallization.
Scratching the inner walls of the glass
other way in order to form crystals
Purity of the sample
The physical properties are dependent on the
Melting point
is defined as the temperature at which the solid changes to liquid.
Eutectic point
ia characteristic of mixture.
Fisher johns or the Nalge Axelrod melting point apparatus
An alternative method of determining melting point is by the use of special equipment such as