The key difference between solvation and hydration is that solvation is the process of solvent and solute molecules’ reorganization into solvation complexes, whereas hydration refers to the process of adding a water molecule to an organic compound.
Solvation and hydration are two important processes in chemistry. Solvation is the dissolution of a substance in a particular solvent. Moreover, solvation of a solute by water is called hydration.
CONTENTS
1. Overview and Key Difference
2. What is a Solvation
3. What is a Hydration
4. Solvation vs Hydration in Tabular Form
5. Summary – Solvation vs Hydration
What is Solvation?
Solvation can be described as the dissolution of a substance in a particular solvent. This process occurs due to the attraction force between molecules of the solvent and the solute molecules. Typically, the attraction forces involved in this process are ion-dipole bonds and hydrogen bonding attractions. These attraction forces cause the dissolution of a solute in a solvent.
The ion-dipole interactions can be found between ionic compounds and polar solvents. For example, water is a polar solvent. When sodium chloride is added to water, the polar water molecules attract the sodium ions and chloride ions separately, which causes the sodium and chloride ions to break apart. This results in the breakdown of the sodium chloride ionic compound.
What is Hydration?
Hydration can be described as the addition of a water molecule to an organic compound. The organic compound is typically an alkene, which has a double bond between two carbon atoms. The water molecule combines this double bond in the form of a hydroxyl group (OH–) and a proton (H+). Therefore, the water molecule dissociates into its ions before this addition. The hydroxyl group is attached to one carbon atom of the double bond, while the proton is attached to the other carbon atom.
Since it involves bond breaking and bond forming, the reaction is highly exothermic. That means; the reaction releases energy in the form of heat. It is a stepwise reaction; in the first step, the alkene acts as a nucleophile and attacks the proton of the water molecule and binds with it through the less substituted carbon atom. Here, the reaction follows the Markonikov rule.
The second step includes the attachment of the oxygen atom of the water molecule to the other carbon atom (highly substituted carbon atom) of the double bond. At this point, the oxygen atom of the water molecule carries a positive charge because it bears three single bonds. Then comes another water molecule which takes up the extra proton of the attached water molecule, leaving the hydroxyl group at the less substituted carbon atom. Thus, this reaction leads to the formation of an alcohol. However, alkynes (triple bond containing hydrocarbons) can also undergo a hydration reaction.
What is the Difference Between Solvation and Hydration?
Solvation and hydration are two important processes in organic and inorganic chemistry. The key difference between solvation and hydration is that solvation is the process of solvent and solute molecules’ reorganization into solvation complexes, whereas hydration refers to the addition of a water molecule to an organic compound.
The following table summarizes the difference between solvation and hydration.
Summary – Solvation vs Hydration
Solvation can be described as the dissolution of a substance in a particular solvent. Hydration can be described as the addition of a water molecule to an organic compound. When the solvent is water, hydration is similar to the solvation process. The key difference between solvation and hydration is that solvation is the process of solvent and solute molecules’ reorganization into solvation complexes, whereas hydration refers to the addition of a water molecule to an organic compound.
Reference:
1. “Solvation.” An Overview | ScienceDirect Topics.
Image Courtesy:
1. “Molecular orbital representation of the electronic states in the first solvation shell in water” By Argonne National Laboratory (CC BY-NC-SA 2.0) via Flickr