a)Rank the following 3 tetrachloride compounds in terms of increasing boiling point: carbon tetrachloride (CCl4), methane (CH4), dichloromethane (CH2Cl2)

b) Which molecule ( KI or LiF ) has the higher boiling point?

c)Select the single most important reason below to justify your choice should have the higher melting point

- Both molecules are nonpolar but the higher melting includes hydrogen bonding
- Both molecules are nonpolar but the higher melting is more polarizable
- The higher melting molecule is polar and the other is not
- The lower melting molecule is polar and the other is not
- The higher melting molecule has smaller Van der Waals forces than the lower melting
- The higher melting molecule has greater Van der Waals forces than the lower melting
- The higher melting molecule is ionic and the other is not
- The lower melting molecule is ionic and the other is not
- The higher melting molecule has hydrogen bonds and the other does not
- The lower melting molecule has hydrogen bonds and the other does not
- Both molecules are ionic but the higher melting has a larger cohesive energy
- Both molecules are ionic but the lower melting has a larger cohesive energy
- The higher melting molecule is ionic and the other is not.
- Ionic bonds are stronger than hydrogen bonds
- The lower melting molecule is ionic and the other is not.
- onic bonds are weaker than hydrogen bonds
- The higher boiling molecule is ionic and the other is not.
- Ionic bonds are stronger than Van der Waals forces
- The lower boiling molecule is ionic and the other is not.
- Ionic bonds are weaker than Van der Waals forces

a) CH4 < CH2Cl2 < CCl4

b) LiF
c) - Both molecules are ionic but the higher melting has a larger cohesive energy

enjoy ;)

a) To rank the tetrachloride compounds in terms of increasing boiling point, we need to consider the intermolecular forces present in each compound. The strength of intermolecular forces determines the boiling point.

Carbon tetrachloride (CCl4) is a nonpolar molecule. It experiences only London dispersion forces, which are relatively weak compared to other intermolecular forces.

Methane (CH4) is also a nonpolar molecule and only experiences London dispersion forces.

Dichloromethane (CH2Cl2) is a polar molecule. It has a dipole moment due to the difference in electronegativity between carbon and chlorine. In addition to London dispersion forces, it also experiences dipole-dipole interactions.

Based on these considerations, the ranking of the compounds in terms of increasing boiling point is: methane (CH4) < carbon tetrachloride (CCl4) < dichloromethane (CH2Cl2). The nonpolar molecules (methane and carbon tetrachloride) have weaker intermolecular forces compared to the polar molecule (dichloromethane).

b) To determine which molecule (KI or LiF) has the higher boiling point, we need to consider the type of bonding and the strength of the intermolecular forces in each compound.

KI is an ionic compound composed of potassium (K) and iodine (I). Ionic compounds have strong electrostatic attractions between positively and negatively charged ions. These ionic bonds result in strong intermolecular forces, which typically lead to higher boiling points.

LiF is also an ionic compound composed of lithium (Li) and fluorine (F). Similar to KI, LiF has strong intermolecular forces due to its ionic lattice structure.

Both KI and LiF have similar bonding types (ionic) and similar intermolecular forces (strong). Therefore, the decision on which one has a higher boiling point cannot be determined solely based on these factors.

c) Out of the given choices, the single most important reason to justify which molecule should have the higher melting point is: "The higher melting molecule is ionic, and the other is not." Ionic compounds generally have higher melting points compared to covalent compounds due to the stronger electrostatic forces between the ions.

I hope this explanation helps you understand the reasoning behind the answers.