Question

(1 point) Hydrogen fluoride (HF) has a lower molecular weight compared to hydrogen chloride (HCl), yet its boiling temperature is much higher. Choose the best explanation for this phenomenon: . A. The chlorine atom has a lower electronegativity than fluorine, thereby making the bond within the molecule weaker OB. The equilibrium distance between atoms within the HF molecule is smaller than that for the HCI molecule C. None of these OD. Two types of secondary (or intermolecular) bonding are present between hydrogen fluoride molecules, whereas only one type of secondary bonding is present between hydrogen chloride molecules O E. The bond between hydrogen and chlorine has greater ionic character compared to that of hydrogen and fluorine OF. none of the above

Answer 1

Hydrogen fluoride (HF) has a higher boiling temperature compared to hydrogen chloride (HCl) due to the formation of hydrogen bonding. The difference in electronegativity between hydrogen and fluorine, along with the small size of the atoms, creates highly concentrated partial charges and strong intermolecular forces in HF.

Step-by-step explanation:

The boiling temperature of hydrogen fluoride (HF) is much higher than that of hydrogen chloride (HCl) despite HF having a lower molecular weight. This is because HF is capable of forming hydrogen bonding within its compounds. Hydrogen bonding occurs when a molecule contains a hydrogen atom bonded to a highly electronegative element, such as fluorine. Due to the very large difference in electronegativity between hydrogen and fluorine, as well as the small size of hydrogen and fluorine atoms, highly concentrated partial charges are created. These strong hydrogen bonds lead to higher intermolecular forces in HF, resulting in a higher boiling point compared to HCl.

Answer 2

The correct option is: D. Two types of secondary (or intermolecular) bonding are present between hydrogen fluoride molecules, whereas only one type of secondary bonding is present between hydrogen chloride molecules

Step-by-step explanation:

Boiling point of a chemical substance depends on the molecular mass and the intermolecular forces, which are the interactive forces present between chemical species

1. The molecular mass of hydrogen fluoride (HF) is less than hydrogen chloride (HCl).

2. But the intermolecular forces present between the HF molecules are stronger than the intermolecular forces present between the HCl molecules.

This is because hydrogen fluoride exhibits two types of intermolecular forces: strong hydrogen bonding and dipole-dipole interactions. Whereas, hydrogen chloride exhibits only one type of intermolecular force i.e. dipole-dipole interactions.

Therefore, as a net result, the boiling point of HF is higher than the boiling point of HCl.