This article illustrates the solubility of ketones, it also explains some questions: Why are ketones Soluble in Water, NaOH, HCl, Ether, Diethyl ether, and H2SO4. Are all Ketones soluble in water and What are ketones soluble in?
Ketones are the carbonyl group and due to the presence of lone pairs on the oxygen atom ketone becomes polar because there is the generation of electronegativity difference between oxygen and a carbon atom.
Are ketones soluble in water?
Ketones consist of the carbonyl group and due to the presence of lone pairs on the oxygen atom ketone becomes polar because there is the generation of electronegativity difference between oxygen and a carbon atom. Lower ketones are soluble in water. Ketones do not form Hydrogen bonds themselves but they show hydrogen bonding with water molecules. Thus it makes ketone soluble in water.
As small molecules of ketone are easily soluble in water but as the chain of the molecules increases, they are difficult to soluble in water. This can happen as one slightly positive charge of hydrogen is enough to attract the lone pair electrons of oxygen for the formation of the hydrogen bond. Another thing is that there is the presence of dispersion and dipole-dipole Vanderwaal forces take place between the molecules.
Are all ketones soluble in water?
Generally, All ketones have the nature to be soluble in water, but as the chain length of the alkyl group increases their solubility decreases. So no, all ketones are not soluble in water. In water, small ketones form hydrogen bonds with water molecules and are soluble. But as the chain length increases the solubility decreases, as a result, there is less energy is released and the reaction becomes less favorable making higher ketone less soluble in water.
Reason for insolubility:
Smaller ketones contain a highly polar group of carbonyl that helps to make the strongest bond with water molecules, that is why they are soluble in water. But in contrast to Higher ketones, the chain length increases which makes the tail portion of ketones non-polar, due to hydrocarbon groups present in them and that decreases the energy and less favorable. That is why not all ketones are soluble in water.
What are ketones soluble in?
Smaller ketones like propanone are soluble in all proportions of water, but as the chain length of ketones increases their solubility decreases. Generally, higher ketones are soluble in organic solvents such as ether, methanol, chloroform, benzene, etc.
Why are ketones soluble in water?
Reason: Polar molecules dissolve in a polar solvent. A polar solvent such as water and ketone are polar due to the presence of lone-pairs on oxygen atoms. Ketones are soluble in water the reason that there is hydrogen bonding between lower molecules of ketones with water molecules that’s why they are easily soluble in water. These ketones do not form hydrogen bonding with themselves, bonding between them is due to the reasons of two forces that affect them as follows:
- Dispersion force
- Dipole – Diploe attraction
This attraction forces release the energy that needs to help break down the water molecules bond with ketones. But as the chain length increases it will decrease the solubility of ketone in water molecules due to the bigger hydrocarbon chain. Unlike hydrogen bonds with other molecules, hydrogen bonds with water molecules do not occur between ketones. Propanone is a lower ketone, that is miscible in water in all the proportions of water.
Are ketones soluble in NaOH?
Ketones are polar molecules, being polar they are soluble in water because water is also polar. This will happen due to dipole interaction with each other and there is H-bonding between ketones and hydrogen of water molecules. Lower ketones are soluble in water molecules but higher ketones are insoluble and firstly tested with a 5% solution of NaOH which ionize the molecules and helps in solubility.
The solubility of ketones in NaOH is due to the presence of one reaction which is Aldol Condensation.
Aldol condensation :
Usually, this reaction occurs in Carbonyl compounds in which Alpha Hydrogen or Alpha carbon is present. In the case of Ketone(Propanone), there is the presence of Alpha carbon which consists of Alpha hydrogen. This reaction will lead increase in the chain length.
Propanone(CH3-CO-CH3 ) is three carbon compounds, out of three two carbon are alpha carbons with alpha hydrogen and the other is one is in the carbonyl group. In the end, we are left with Alpha- and beta-unsaturated products.
Thus ketones are soluble in Strong Bases like NaOH and the reaction is as follows:
In this reaction, there is the production of two different products, these are beta-hydroxy ketones and beta-hydroxy aldehyde.
Are ketones soluble in HCl?
Ketones are soluble in Conc.HCl due to its polar nature and in presence of Zinc amalgam carbonyl group reduces into the CH2 group. This Reaction is called Clemmensen Reduction.
Example: Propanone (CH3-CO-CH3 ) reduces to propane in presence of Zn/Hg(Zinc Amalgam) and concentrated HCl.
Is ketone soluble in the ether?
Usually, Ketone is soluble in Organic solvents like ethers. Ketones’ boiling point is higher than that of ether due to dipole interaction in ketones.
When intermolecular forces of two substances are similar then there is intermixing takes place. Ketones and ether are miscible due to dispersion and dipole interaction between them here are no H-bonding but dipole interaction due to which it is soluble in organic solvents. Lower ketones are soluble in water molecules but higher ketones are insoluble, they are soluble in organic solvents whose nature is polar.
Are ketones soluble in diethyl ether?
Diethyl ether(C2H5)2O, contains oxygen atoms and has dipole moment and bond angle due to which it becomes polar and this will make it polar as ketone is polar that has properties soluble in polar compounds. Thus Ketones(R2 C=O) are soluble in Diethyl ethers.
These ketones do not form hydrogen bonding with themselves, bonding between them is due to the reasons of two forces that affect them as follows: Dispersion force and Dipole – Diploe attraction this attraction forces release the energy that needs to help break down the water molecules’ bond with ketones. But as the chain length increases it will decrease the solubility of ketone in water molecules due to the bigger hydrocarbon chain.
Why are ketones soluble in H2SO4?
The compounds that contain Oxygen and nitrogen in their functional group are generally soluble in concentrated Sulphuric acids (H2SO4). There is self-reaction that takes place in the presence of concentrated sulphuric acid, formation of aromatic compounds occurs.
Ketones react with acid to undergo condensation reactions and this reaction is called an acid-catalyzed aldol condensation reaction. Acetone(Propanone) is absorbed by sulphuric acids(H2SO4) at a 75% concentration of acid in the solution and the reaction is irreversible.