Why is acetone polar

What is Acetone?

Acetone is an organic liquid which is defined chemically with the formula (CH3)2CO, and is also known as the simplest form of ketone. Otherwise identified as propanone, this is a compound which is highly flammable and totally colorless. The production of acetone is currently achieved with the help of the cumene process on propylene. Acetone is actually a very popular polar solvent used primarily in laboratories for both cleaning purposes and for the production of chemicals such as methyl methacrylate and bisphenol A. Even inside the systems of animals and human beings, acetone is produced and excreted out on a regular basis. Propanone may contaminate ground water (and it often does), which may in turn reduce the level of oxygen in water due to the action of microbes on them, thereby affecting aquatic life forms.

Why is it Polar?

As mentioned above, acetone is mainly a solvent and solvents are either polar or non-polar. The polarity of a solvent is determined primarily based on its dielectric constant. Dielectric constant is the relative permittivity of any solvent, explained via the following equation:

acetone formula

The polarity of a solvent is considered to be non-polar if its dielectric constant is anything below 15. Similarly, any solvent with a relative permittivity above 15 would be considered polar. A highly polar solvent will have the ability to weaken the electromagnetic field around the charged particle. In terms of physics, the field strength of the particle in question (vacuum) is similar to the decrease in the charged particle’s field by the action of the polar solvent. Since acetone has a dielectric constant of 21 as well as a dipole moment of 2.88 Debyes, it can be concluded that acetone is indeed quite polar.

In fact, compared to other organic solvents like ethanol, acetone has a higher polarity, thanks to its sp2 hybridized carbon atom. Most other organic solvents have the sp3 hybridized carbon atom attached to their oxygen atoms, which make solvents like ethanol, less polar.

Acetone is Also Aprotic

In addition to being highly polar, acetone is also an aprotic solvent. It is the liquid’s inability to bond with any of the hydrogen atoms present in it, that makes acetone aprotic. Nonetheless, hydrogen atoms are certainly present, but in spite of having oxygen, the OH bond just does not happen in acetone as the oxygen always bonds with the carbon instead of hydrogen atoms. Ethers, dimethylformamide and dimethylsulfoxide are all aprotic solvents. As one can guess, protic solvents are the exact opposite of aprotic solvents due to the fact that in them, hydrogen bonding is mandatory and occurs freely. Water and alcohol are both protic liquids that allow bonding between hydrogen and other elements.

The aprotic nature of the solvent allows acetone to separate the cations and anions of the solute particles, assisted in particular by its large dipole moments. Once the separation part is over, then begins the dissolution, which is achieved when the negative dipoles of the solvent attaches themselves with the positive ions of the solute.