Question

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.

Short answer

The following substance have higher boiling point:

1. ${\mathbf{CH}}_3\mathbf{OH}$
   
2. $\mathbf{FNO}$
   
3. 
   

Step-by-step solution

Intermolecular interactions

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.

Effect of interactions on the boiling point

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.