Question

definition of drying agent and briefly explain about ir

Answer 1

Drying agents (also called desiccants) come in various forms and have found widespread use in the foods, pharmaceuticals, packing, electronics and many manufacturing industries. A desiccant is a hygroscopic substance that induces or sustains a state of dryness in its vicinity. Ideally, it is chemically stable and chemically inert (i.e., silica). Unfortunately, this is not always the case in the chemistry lab because the drying agent comes into direct contact with the solvent and the chemical.

Many organic solvents are immiscible with aqueous solutions, but they are able to dissolve significant amounts of water because of their polarity i.e., diethyl ether dissolves 7 % of its weight in water while tetrahydrofuran is completely miscible with water (Why?). Unfortunately, water is a compound that is very difficult to remove from many compounds, because they are either holding on to it well (i.e., alcohols) or the compound itself is steam volatile. Bottom-line is that the more polar the solvent is, the more hygroscopic it will usually be because it dissolves the water better. Thus, removing water and other impurities from a solution can become an arduous task but is necessary if the reagents are also sensitive towards water i.e., Grignard reagents or in cases where water has a detrimental effect on the yield or rate of the reaction. In those cases, drying agents like calcium hydride (CaH2), sodium metal (in combination with benzophenone) or lithium aluminum hydride (LiAlH4) are used to chemically destroy the water in the solvent. Those compounds are relatively reactive and difficult to handle and usually not used in lower division undergraduate laboratories

Answer 2

A drying agent is a chemical used to remove water from an organic compound that is in solution. In making or isolating chemical compounds they often become contaminated with water. If you want to dry a compound that is in solution, a saturated (highly concentrated) solution of sodium chloride can be used to remove the extra water. Water will move from an area of higher concentration (the compound solution) to an area of lower concentration (the saturated salt solution). You will get 2 layers: the salt solution layer and the layer of "dried " organic compound solution. The pure compound can then be separated from the salt solution layer. Drying agents can also be solid like Calclium chloride, Potassium chloride, or Magnesium sulfate. These are all types of salts (ionic compounds where metals are bonded to nonmetals.) These drying agents are added to the solution of a compound that needs to be dried. The agents will easily pick up any extra water from the compound solution and become hydrated. The hydrated salts form clumps which can be filtered out or left behind during decanting resulting in a "dry" compound. Hope it helps please mark as branliest