Question

Is acetone protic or an aprotic polar solvent?

Answer 1

Hint: We have to know that acetone contains a ketonic group in it. It does not have a hydroxyl group i.e. $O - H$ group. Acetone, or propanone, is an organic compound with the formula ${\left( {C{H_3}} \right)_2}CO$. It is the simplest and smallest ketone. It is a colorless, highly volatile and flammable liquid with a characteristic pungent odor.

Complete answer:
Before starting this question we must know about protic and aprotic solvent. Protic solvents; We need to know that the solvate anions (negatively charged solutes) strongly via hydrogen bonding. Water is a protic solvent. Aprotic solvents tend to have large dipole moments (separation of partial positive and partial negative charges within the same molecule) and solvate positively charged species via their negative dipole. So we can say that acetone is an aprotic polar solvent. Polar solvents contain bonds between atoms with very different electronegativities, such as oxygen and hydrogen, and have large dipole moments. Non-polar solvents contain bonds between atoms with similar electronegativities, such as carbon and hydrogen. These polar solvents are capable of forming hydrogen bonds with water to dissolve in water whereas non-polar solvents are not capable of strong hydrogen bonds. Polar aprotic solvents contain no hydrogen atoms connected directly to an electronegative atom and they are not capable of hydrogen bonding.

Note:
We have to remember that the \[{S_N}1\] reaction works well for tertiary alkyl halide because the loss of the leaving group forms a tertiary carbocation which is the most stable form of carbocation. A polar protic solvent will stabilize this carbocation. But \[{S_N}2\] reactions do not work well in polar protic solvents because these solvents weaken the nucleophile making it less nucleophilic.