Are Ketones Polar:5 Facts You Should Know


In this article, we will illustrate are ketones polar and their Fact, and also explain How are ketone polar, why ketones are more polar, why are ketones more polar than an ester, and why ketones are more polar than amines.

Ketones are the functional group and it is related to the carbonyl group. In this carbon is bonded with oxygen and other alkyl groups. Ketones group present in Sugar and work in our body effectively.  Below we will See 5 facts about ketone’s polarity.

Ketones are Polar:5 Facts 

Ketones are polar due to the facts: 

  1. Ketones are highly polar molecules than aldehyde and ester.  
  1. Ketones do not have a hydrogen bond that is directly attached to the oxygen atom.  
  1. Ketones are highly reactive   
  1. Due to electronegativity difference, there is the formation of dipole and dipole-dipole interaction occurs.  
  1. Vanderwall dispersion occurs in ketone molecules. 

How are ketones Polar? 

Firstly, we will explain about Carbonyl Group: Carbonyl Group consists of a carbon-oxygen double bond. The Hybridization of carbon is SP2. The Structure of the Carbonyl group is a Trigonal planner, consisting 3-sigma bond and one pi bond and a 120-degree angle are present between each bond. So, these bonds are polar due to the electronegativity difference between carbon and oxygen atom.

Ketones are examples of a carbonyl group consisting of carbon-oxygen double bonds(R2C=O). Here R2 means the alkyl group attached to the carbon atoms. R2 will affect the polar nature of ketone. Ketones have no hydrogen bond but they form a hydrogen bond with water molecules. However, the ketone is highly polar but it does not have a direct bond with hydrogen. Example: Propanone, Butanone  

Polarity of ketones

Why are ketones more polar?

Ketones are more polar due to the electronegative difference being more, therefore, carbon and hydrogen, oxygen attracts electrons from carbon, and due to this, there is the generation of slightly positive and negative charge on it. This difference creates a polar molecule and that’s why ketones have become polar.

For example, Ketone has higher boiling points due to the presence of the alkyl group that donates electrons, around the C=O groups and makes the molecules higher polar. During the reaction, a double bond between carbon and oxygen is broken and this will lead to the formation of Water molecules. 

are ketones polar
Generation of the dipole in Ketone

Reason: 

  1. Oxygen having lone pair is more electronegative than carbon.  
  1. The Carbonyl group is polar due to a slightly negative charge on oxygen and positive charge on carbon and this creates a dipole.  
  1. Due to this dipole generation ketone becomes polar.  
  1. And polarity of ketones influences chemical and physical properties.   
  1. This Dipole creates Vanderwall dipole-dipole attractions. As the dispersion forces increase there is the generation of the dipole to the nearest atom.  

Nucleophilic attack on Carbonyl Group as Shown below:

Nucleophile attack on Carbonyl Group

Are ketones more polar than esters?

Ester properties are very similar to that of ketones but they are less polar than ketones the reason behind it is that the polarity of the ester is not enough to make it more polar.

Ester has the chemical formula RCOOR having a carbonyl group formed from carboxylic acids, alchole, and some inorganic acids. Ester has an alkoxy group which is formed by replacing the hydroxyl group in carboxylic acids  

Being the presence of carbonyl group ketone and ester, both are polar but ketone is more polar than ester due to the difference in dipole-dipole attraction and difference in Vanderwaal’s force of dispersions. Ester has a weaker bond formation Ester has a weaker hydrogen bond formation and their dipole-dipole interaction is weaker than ketones. The boiling point of the ester is lower than that of ketones due to the presence of carbonyl bonds.  

Are ketones more polar than amines?  

Amines have hydrogen bonds but ketones are not having hydrogen bonds and this will make ketones more polar due to the presence of oxygen atoms. And more electronegative oxygen atoms present in the ketone make it more polar than amines.

Reason: The electronegativity of oxygen is more than that of nitrogen due to this oxygen attracts more electrons towards itself and the molecule becomes more polar than the nitrogen atom.

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