The most polar is acetone. Acetone is polar. That is part of the reason it mixes with water. It is also soluble with nonpolar substances like hydrocarbons because of the two methyl side groups. Solution The most polar is acetone. Acetone is polar. That is part of the reason it mixes with water. It is also soluble with nonpolar substances like hydrocarbons because of the two methyl side groups..