Question

For each pair of molecules, predict which would have the highest boiling point:

a. CH4 versus CH3Cl

b. HF versus HCl

c. CH3CH3OH versus CH3CH2F

d. CH4 versus CI4

e. PH3 versus NH3

Answer 1

a. CH4 versus CH3Cl
CH3Cl has greater boiling point as CH3Cl have dipolar interaction whereas CH4 are having London forces

b. HF versus HCl
HF has greater boiling point because HF can form hydrogen bonding whereas H-Cl have just dipolar interaction

c. CH3CH3OH versus CH3CH2F
CH3CH3OH has greater boiling point because CH3CH3OH can form hydrogen bonding

d. CH4 versus CCI4
CCl4 will have somewhat greater boiling point because of larger molar mass of CCl4 since both CCl4 and CH4 are non polar

e. PH3 versus NH3
NH3 will have greater boiling point due to hydrogen bonding in NH3