Question

Why does H2O have a higher boiling point than SO2. Explain in terms of molecular geometry and intermolecular forces.

Answer 1

@Abhisar

Answer 2

Because H\(_2\)O have hydrogen bonding.

Answer 3

could this be right: H-bonded molecules will have the highest boiling point that’s because none of the molecules exhibit ion-dipole forces.

Answer 4

Hydrogen bonds are special interactions that can occur between the hydrogen of one molecule and the oxygen, fluorine and nitrogen of another molecule. These are especially electronegative elements and in a compound such as water (H2O), the electrons which are shared between the hydrogens and the oxygen in forming the two single bonds have a greater attraction towards the more electronegative oxygen. So, this oxygen atom will develop a temporary negative charge or temporary 'diplole', whilst the hydrogens develop a positive dipole, as the negatively charged electrons they shared to form the bonds in water have been dragged away from them.



Covalent bonds in which this occurs are called polar covalent, and the more electronegative the element dragging the electrons towards itself, the greater the dipole. In a solution containing so many of these molecules floating around, this leads to strong interactions as the positive (Hydrogen) end of one molecule is attracted to the negative (Oxygen) end of another. These form 'Hydrogen Bonds', which are quite weak on their own but have a massive effect as they are repeated amongst billions of identical molecules together, and ate therefore difficult to break apart. This is why water has a higher boiling point, as it is more difficult to separate all the molecules away from one another to form a gas. SO2, with the less electronegative sulfur atom, does not have as great a dipole or interactions, and thus it is easier to form as gas with and it has a lower boiling point. Hope that helps! :)