Distinguish between drying and dehydrating agent.
Distinguish between drying and dehydrating agent.
Drying agent Drying agent (a) They remove moisture from other substances
(b) They are used to dry gases like chlorine, Sulphur dioxide They are used in desiccatorsto keep substances dry
(c) They represent physical change
(a)They remove chemically They remove chemically the ratio of 2:1 from acompound.
(b) They prepare substances like carbon monoxide, sugarcharcoal etc.
(c) They represent chemical change
Dehydrating agents remove water which is chemically bound to a substance for e.g water of crystallization. While on the other hand a drying agent simply removes excess water present in a substance which is not chemically bound to it.
A drying agent simply absorbs the moisture or water vapour that is present as an impurity or contaminant with the desired substance. It does not act as a reactant to produce a new substance by a chemical reaction, but simply as a purifier.
For example. Concentrated H2SO4 can be used as a drying agent to remove any moisture that is present as impurity with gases like CO2, nitrogen or oxygen.
Anhydrous CaCl2 is another good drying agent used in chemical analysis.
A dehydrating agent, on the other hand, actually acts as a reactant. It helps formation of a new substance by removing some parts of the other reactant as water. It effectively decomposes the other reactant by breaking chemical bonds.
For example, phosphorus pentoxide dehydrates nitric acid to dinitrogen pentoxide when it is distilled with the latter.
Alumina (Al2O3) and conc.H2SO4 are also widely used as dehydrating agents, especially in converting alcohols to alkenes.
| Drying agent | Drying agent |
| (a) They remove moisture from other substances (b) They are used to dry gases like chlorine, Sulphur dioxide They are used in desiccatorsto keep substances dry (c) They represent physical change | (a)They remove chemically They remove chemically the ratio of 2:1 from acompound. (b) They prepare substances like carbon monoxide, sugarcharcoal etc. (c) They represent chemical change |
Dehydrating agents remove water which is chemically bound to a substance for e.g water of crystallization. While on the other hand a drying agent simply removes excess water present in a substance which is not chemically bound to it.
A drying agent simply absorbs the moisture or water vapour that is present as an impurity or contaminant with the desired substance. It does not act as a reactant to produce a new substance by a chemical reaction, but simply as a purifier.
For example. Concentrated H2SO4 can be used as a drying agent to remove any moisture that is present as impurity with gases like CO2, nitrogen or oxygen.
Anhydrous CaCl2 is another good drying agent used in chemical analysis.
A dehydrating agent, on the other hand, actually acts as a reactant. It helps formation of a new substance by removing some parts of the other reactant as water. It effectively decomposes the other reactant by breaking chemical bonds.
For example, phosphorus pentoxide dehydrates nitric acid to dinitrogen pentoxide when it is distilled with the latter.
Alumina (Al2O3) and conc.H2SO4 are also widely used as dehydrating agents, especially in converting alcohols to alkenes.
