For hydrogen chloride gas, which type of intermolecular force is the dominant specific interaction in addition to general dispersion forces?

Introduction / Context:
Intermolecular forces are the attractions between molecules that influence boiling points, melting points and many physical properties of substances. Hydrogen chloride, HCl, is a common example used to illustrate polar covalent molecules and their intermolecular forces. This question asks you to identify the dominant specific intermolecular force in HCl, apart from the general dispersion forces present in all molecules.

Given Data / Assumptions:

• Hydrogen chloride has the chemical formula HCl.
• The bond between hydrogen and chlorine is polar due to a difference in electronegativity.
• Hydrogen bonding requires hydrogen bonded to highly electronegative atoms such as fluorine, oxygen or nitrogen.
• All molecules exhibit dispersion forces, but the question focuses on the characteristic additional force.

Concept / Approach:
HCl is a polar covalent molecule because chlorine is significantly more electronegative than hydrogen, which creates a permanent dipole. Polar molecules experience dipole dipole interactions, where the positive end of one molecule is attracted to the negative end of another. Hydrogen bonding is a special, stronger type of dipole dipole interaction that occurs only when hydrogen is directly bonded to fluorine, oxygen or nitrogen. In HCl, hydrogen is bonded to chlorine, not to F, O or N, so conventional hydrogen bonding is not present. Therefore, the dominant specific intermolecular force, in addition to dispersion forces, is ordinary dipole dipole interaction.

Step-by-Step Solution:
Step 1: Recognise that chlorine is more electronegative than hydrogen, making the HCl bond polar. Step 2: Recall that polar molecules exhibit dipole dipole forces due to the attraction between partial charges on different molecules. Step 3: Check whether HCl can form hydrogen bonds by verifying if hydrogen is bonded to fluorine, oxygen or nitrogen. Step 4: Conclude that since hydrogen is bonded to chlorine instead, typical hydrogen bonding does not occur in HCl. Step 5: Select dipole dipole interaction as the main specific intermolecular force beyond dispersion forces.

Verification / Alternative check:
Comparing boiling points gives an additional check. Substances that show strong hydrogen bonding, such as water, have much higher boiling points than similar sized molecules without hydrogen bonding. HCl has a lower boiling point than water despite having a similar number of electrons, which suggests that strong hydrogen bonding is absent. Textbook discussions also classify HCl as a polar molecule with dipole dipole forces, rather than as a classic hydrogen bonded system like HF, H2O or NH3. This supports the conclusion that dipole dipole interaction is the correct answer.

Why Other Options Are Wrong:
Hydrogen bonding is not typically assigned to HCl in school level chemistry because the hydrogen is not bonded to fluorine, oxygen or nitrogen.
Only dispersion forces would ignore the clear permanent dipole in HCl, so it is incomplete as a description of its intermolecular forces.
Claiming all the options apply equally is incorrect because hydrogen bonding and ionic lattice attractions do not accurately describe HCl as a simple polar covalent gas.
Ionic lattice attraction refers to the forces in ionic solids such as sodium chloride, not to a covalent molecule like HCl under normal conditions.

Common Pitfalls:
Students may be tempted to choose hydrogen bonding whenever they see hydrogen combined with a more electronegative atom, without checking whether it is one of fluorine, oxygen or nitrogen. Another pitfall is to think that all polar molecules must involve hydrogen bonding. Remember that dipole dipole forces are more general and occur in many polar substances, while hydrogen bonding is a special stronger case with very specific requirements.

Final Answer:
The dominant specific intermolecular force in hydrogen chloride, apart from dispersion forces, is dipole dipole interaction.