1. Polar solvents generally have asymmetric molecular structures, so the electron cloud shifts to a large extent and is concentrated near a certain functional group, so it shows polarity. For example, nonpolar solvents such as methanol, ethanol, tetrahydrofuran, DMF, DMSO, etc., on the contrary, have symmetrical molecular structure and uniform distribution of electron clouds. For example, petroleum ether, n-hexane, toluene, benzene, etc.

2. The concept and definition of nonpolar solvent refers to a kind of solvent with low dielectric constant, also known as inertsolvent. This kind of solvent does not undergo proton autotransfusion reaction or solvation with solute. Most of them are saturated hydrocarbons or benzene and other compounds. Such as benzene, carbon tetrachloride, dichloroethane, etc. The nonpolar solvent is composed of fattyoils, liquid paraffin (1 iquiparaffin), ethyloleate and isopropylmyristate. Non-polar solvents are solvents composed of non-polar molecular solutions. Non-polar molecules are mostly composed of valence bonds with no electrons or little electronic activity. Also refers to the solvent with small dipole moment. Commonly used nonpolar solvents are chloroform, benzene, liquid paraffin, vegetable oil, ether and so on. The dielectric constant of nonpolar solvents is very low, which can not weaken the attraction of electrolyte ions and form hydrogen bonds with other polar molecules. However, the dissolution of nonpolar substances by nonpolar solvents is the result of van der Waals force between solute and solvent molecules, and the instantaneous dipole generated inside the solvent molecules.