Question

The reason iodine, I2, exists as a solid at room temperature, while bromine, Br2, exists as a liquid at the same temperature, is because:
Iodine exhibits hydrogen bonding, while bromine exhibits only London dispersion forces.

Iodine molecules create stronger London dispersion forces than do bromine molecules.

Bromine exists only as a gas at all temperatures.

Bromine forms fewer dipole-dipole interactions than does iodine.

Answer 1

Answer: Option (b) is the correct answer.

Explanation:

London dispersion forces are defined as weak intermolecular forces due to temporary opposite charges on the combining atoms.

London dispersion forces depend on the size of an atom. More is the size of atoms more will be the London dispersion forces present within a molecule. Hence, substance will exist as a solid.

Since, bromine is smaller in size than iodine so, bromine molecules will have weak London dispersion forces between them.

On the other hand, iodine being larger in size so, its molecules will have strong London dispersion forces.

Therefore, we can conclude that the reason iodine, $I_2$, exists as a solid at room temperature, while bromine, $Br_2$, exists as a liquid at the same temperature, is because: Iodine molecules create stronger London dispersion forces than do bromine molecules.

Answer 2

The reason iodine, I2, exists as a solid at room temperature, while bromine, Br2, exists as a liquid at the same temperature, is because: Iodine molecules create stronger London dispersion forces than do bromine molecules.