Why can some nonpolar substances be liquids at room temperature? Solution Some Non polar substances are liquid at room temperature.phase of a substance is decided by forces of attraction between molecules of a substance.non polar substances do not have dipole moment so they do not have dipole-dipole attraction forces.so their phases are decided by wanderwaal dispersion forces which depends upon molecular wight of substance.higher the molecular weight stronger will be the wanderwaal forces of attraction.substances having low molecular weight will have weak wanderwaal forces so their molecules tends to move freely so they are liquid like carbon tetrachloride. So substances having weak forces of attraction are liquid at room temperature. .