Question

Classify the following mixtures of liquids into (A) those with London Dispersion forces between the two molecules (B) those with London Dispersion forces and dipole-dipole attraction between the two molecules (C) those with London Dispersion forces, dipole-dipole attraction and hydrogen bonding between the two molecules |1-propanol and 1-butanol 1,1,2,2-tetrachloroethane and ethanol methylbenzene and 1,2-dimethylbenzene trichloromethane and dichloromethane benzene and cyclohexane bromobutane and ethanol

Answer 1

1-propanol and 1-butanol : In these all three (type C) forces are present

London Forces : between non polar alkyl part

H-Bond : Between H-O.......H-O of alchohos

Dipole dipole due to electronegativity difference of alkyl part and OH part

1,1,2,2-tetrachloroethane and ethanol : only London dispersion forces and dipole dipole interaction (Type B)

since tetrachloroethane is non polar and only have weak vanderwaal forces or london forces

methylbenzene and 1,2-dimethylbenzene : both are non polar so only London Forces

trichloromethane and dichloromethane : dipole dipole interaction (Type B) since both are polar ( london forces always operate becasue of size and hydrophobic group)

benzene and cyclohexane : both are non polar so only London Forces

bromobutane and ethanol : dipole dipole interaction (Type B) since both are polar