Question

A solution containing methanol (CH3OH) and naphthalene (C10H8) were to be separated by chromatography. The stationary phase (solid phase coated on the column) contained Cl- ions at the surface.

a) Name and describe the intermolecular forces that occur between the stationary phase and the two molecules as they pass through the column. Rank the IMF in strength from lowest to highest.

b) Determine the order of elution of the two molecules as they elute from the end of the column and are detected. Explain.

Answer 1

Answer – There is given solution containing methanol (CH3OH) and naphthalene (C10H8) were to be separated by chromatography and stationary phase contained Cl- ions at the surface.

a) We know the methanol (CH3OH) is the polar molecule and naphthalene (C10H8) is the nonpolar molecule. The given stationary phase is with Cl^- ion, so there is strong intermolecular force between methanol and Cl^- and form the ion-dipole intermolecular force. There is methanol has dipole-dipole intermolecular force.

There is naphthalene (C10H8) is the nonpolar molecule so there is no any interaction between the Cl^- ion and only London dispersion force. So there is ion-dipole is the highest intermolecular force then dipole-dipole and then London dispersion force.

b) As we know there is naphthalene (C10H8) is the nonpolar molecule and it is interacting with Cl^- ion means with stationary phase it is move faster in the column and this elute collected firs. There is ion-dipole interaction between Cl^- ion and methanol, so it moves very slowly and collected secondly.