Which substance has the highest boiling point? Why? Hint: They are all nonpolar.
(a) \(\mathrm{CH}_{4}\)
(b) \(\mathrm{CH}_{3} \mathrm{CH}_{3}\)
(c) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{3}\)
(d) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{3}\)
Equation Transcription:
Text Transcription:
CH_4
CH_3 CH_3
CH_3 CH_2 CH_3
CH_3 CH_2 CH_2 CH_3
Solution 69P
Among all substance, only (d) CH3CH2 CH2 CH3 has the highest boiling point. This is because of the greater amount of dispersion force act on it. Since, the magnitude of the dispersion force depends on the electrons in the atom or molecule which can polarize in response to an instantaneous dipole. This is dependent on the size (or volume) of the electron cloud. The dispersion force would be high when the electron cloud become more which is due to the loose bound with the nucleus and thus polarize easily. Thus, electron cloud will be more when molecules have higher molar mass which results higher dispersion force.
Thus, among all substance, (d)CH3CH2 CH2 CH3 has higher molar mass which corresponds to the increasing dispersion force that results higher in boiling point.
