Question

Rank the following substances in order of increasing boiling points: H2O, Br₂, KCl, HCI

HCl
Br₂ Br₂ Br₂

Answer 1

Br2 has the lowest boiling point, followed by HCl, then H2O, and KCl has the highest boiling point, due to the increasing strength of their intermolecular forces and ionic bonding.

Step-by-step explanation:

To rank the following substances in order of increasing boiling points: H2O, Br2, KCl, HCl, we need to consider the types of bonding and molecular forces present in each substance. Generally, ionic compounds like KCl have higher boiling points due to their strong ionic bonds. Molecular substances like Br2 have lower boiling points because their intermolecular forces (like London dispersion forces) are weaker.

1. Br2: As a diatomic molecule, it relies on London dispersion forces and exhibits the lowest boiling point among these substances.
2. HCl: This polar covalent molecule has dipole-dipole interactions, plus London dispersion forces, leading to a moderate boiling point.
3. H2O: Water has a high boiling point due to its ability to form hydrogen bonds, which are stronger than other dipole-dipole interactions.
4. KCl: As an ionic compound, potassium chloride has the highest boiling point because of the strong electrostatic attraction between its ions, which requires significant energy to overcome.

Answer 2

The substances in increasing order of boiling points are H2O, KCl, HCl, Br2.

Step-by-step explanation:

The boiling point of a substance is determined by its intermolecular forces. The stronger the intermolecular forces, the higher the boiling point. In this case, the substances are:

1. H2O
2. KCl
3. HCl
4. Br2

H2O has hydrogen bonding, which is the strongest intermolecular force among the substances. KCl and HCl have ionic bonding, which is weaker than hydrogen bonding. Br2 has only van der Waals forces, which are the weakest intermolecular forces.