Question

Which compound in each of the following pairs would have the higher boiling point:
A.$C{H_3} - C{H_2} - C{H_2}OH\;$ or $C{H_3}C{H_2} - OC{H_3}$
B.$HO - C{H_2} - C{H_2} - OH\;$ or $C{H_3}C{H_2}C{H_2}OH$

Answer 1

To answer this question, you should recall the concept of Intermolecular forces. They are the attractive and repulsive forces that arise between the molecules of a substance. These forces mediate the interactions between individual molecules of a substance

Complete step by step answer:
Intermolecular forces refer to the attractive and repulsive forces that arise between the molecules due to interaction. The boiling point of molecules depends on the intermolecular force of attraction, stronger the force, higher is the boiling point. In a molecule, when a hydrogen atom is linked to a highly electronegative atom, it attracts the shared pair of electrons more and so this end of the molecules becomes slightly negative while the other end becomes slightly positive. The negative end of one molecule attracts the positive end of the other and as a result, a weak bond is formed between them. This bond is called the hydrogen bond. The molecule must contain a highly electronegative atom linked to the hydrogen atom. The higher the electronegativity, the polarization of the molecule. The size of the electronegative atom should be small. The smaller the size, the greater is the electrostatic attraction.
A. $C{H_3} - C{H_2} - C{H_2}OH\;$ is having more boiling point than $C{H_3}C{H_2} - OC{H_3}$ ​ due to intermolecular H bonding in $C{H_3} - C{H_2} - C{H_2}OH$
B. $HO - C{H_2} - C{H_2} - OH\;$ is having more boiling point than $C{H_3}C{H_2}C{H_2}OH\;$ because of more H bonding in case of $HO - C{H_2} - C{H_2} - OH$ than $C{H_3}C{H_2}C{H_2}OH\;$

Note:
You should know about the other types of Intermolecular forces
1. Ion-Dipole Interactions: These interactions arise between ions and polar molecules. The strength of this interaction is proportional to the magnitude of the dipole moment, size disparity and charge disparity of an ion.
2. Ion Induced Dipole Interactions: A non-polar molecule is polarized by an ion placed near it due to induction. Now after this polarization, both behave as induced dipoles.
3. Dipole Induced Dipole Interaction: Non-polar molecules are transformed into induced dipoles due to the presence of a polar molecule nearby.
4. Dispersion Forces or London Forces: Arises due to the movement of electrons thus creating temporary positive and negative charged regions.