Question

Use the References to access important values if needed for this question. List the following substances in order of increasing normal boiling points Tb, and explain your reasoning: He, HCI, HF, Nal Boiling point substance1-lowest Reason 4-highest Is an ionic compound: forces are stronger than forces between neutral molecules. Has hydrogen bonds: stronger than other dipole-dipole interactions Is polar: dipole-dipole forces are stronger than dispersion forces Is nonpolar: dispersion forces are weaker than dipole-dipole forces. HCI HF Nal Submit Answer 1 question attempt remaining

Answer 1

The increasing order of boiling point will be

1. He = -269.9°c

2. HCl = -85.05°c

3. HF = 19.5°c

4. NaI = 1304 ° c

Reasons

1. He - the intermolecular force is very weak due to small atomic size. The other reason is that the interaction is very weak

From your options the correct answer would be

Is nonpolar - dispersion forces are weaker than dipole-dipole forces.

2. HCl - HCl has the smallest london forces and does not have hydrogen bonding.

From your options the correct option would be

Is polar - dipole - dipole forces are stronger than dispersion forces.

And this is the reason it has higher boiling point than he.

3. HF - In HF there is fluorine which is highly electronegative hence lot of energy is required to break the intermolecular forces between them.

From your options the correct answer would be

Has hydrogen bonding - stronger than any other dipole dipole interactions.

4. NaI - NaI is made up of ionic bonds which are very stronger in comparison to normal or neutral bonds.

The correct answer from your options would be

Is an ionic compound - forces are stronger than forces between neutral molecules