Which substance has the higher boiling point? Explain.

a.${\mathbf{CH}}_3\mathbf{OH}$OR${\mathbf{CH}}_3{\mathbf{CH}}_3$

b.$\mathbf{FNO}$ OR $\mathbf{ClNO}$

c.

The intermolecular interactions include the weak London dispersive forces, ion –dipole, dipole-dipole, H-bonding interactions, etc. Depending on these interactions and their strength, the boiling point of the compound differs.

1. Ethane has weak intermolecularLondon dispersive forces whereas methanol has H-bonding interactions in between the molecules.Thus, ethane has low boiling point than methanol.
2. Because, F is more electronegative than Cl, the $\mathbf{FNO}$bond is more polar in comparison to the $\mathbf{ClNO}$. This ensures strongerdipole-dipole interactions in $\mathbf{FNO}$thanrole="math" localid="1658851584584" $\mathbf{ClNO}$ , thus suggesting high boiling point of$\mathbf{FNO}$ in comparison to role="math" localid="1658851579544" $\mathbf{ClNO}$.
3. Because of the electronegativity difference between H and F atom, the -trans compound will ensure more H-bonding interactions than the -cis compound. Thus, the -trans compound have higher boiling point than the -cis compound.