Question

2. Rank the boiling points of methane, methanol, and methanal from lowest to highest. Explain your ranking. (6 points) 3. The lone pair of electrons on the oxygen atom in an ester can form hydrogen bonds in some situations, but esters cannot form hydrogen bonds with each other. How would you expect the boiling point of an ester to compare with that of an alcohol

Answer 1

Answer:

(2) Boiling point order: Methanol (highest) > Methanal > Methane (weakest)

(3) Boiling point of alcohol will be higher than ester molecules

Explanation:

(2) Methane is a non-polar molecule. Hence only weakest van der waal inter molecular force is present between methane molecules.

Methanal is polar molecule due to presence of polar aldehyde group. hence weaker dipole-dipole inter molecular force is present between methanal molecules.

Methanol is a polar protic molecule. Hence strongest H-bonding force act between methanol molecules.

The stronger the inter molecular force, the higher will be boiling point.

Boiling point order: Methanol (highest) > Methanal > Methane (weakest)

(3) An alcohol is a polar protic molecule. Hence strongest H-bonding force exist between alcohol molecules.

An ester is  polar molecule. Therefore weaker dipole-dipole inter molecular force is present between ester molecules.

So boiling point of alcohol will be higher than ester molecules.