Final answer:
The strongest intramolecular force within a molecule is the force that holds the atoms together. For hydrogen (H2), the intramolecular force is a covalent bond, while intermolecular forces vary among molecules with London dispersion forces in nonpolar molecules, dipole-dipole interactions in polar molecules, and hydrogen bonding in molecules with hydrogen bonded to highly electronegative atoms.
Step-by-step explanation:
The strongest intramolecular force present in a molecule determines how it interacts with other molecules and the physical properties it exhibits. Intramolecular forces are the forces that hold atoms together within a molecule. For the molecules you've provided, here are the most significant intramolecular forces:
- Hydrogen (H2) - This molecule is nonpolar and the main intramolecular force is the covalent bond between the hydrogen atoms. When speaking of intermolecular forces (which are between molecules), the force exhibited by H2 is London dispersion forces, as it is a nonpolar molecule. Note that such forces are very weak.
- London dispersion forces are the weakest intermolecular force and are present in all molecules. They result from temporary fluctuations in electron density that create temporary dipoles.
- Dipole-dipole interactions occur in polar molecules where there is an uneven distribution of electrons within the molecule, leading to a permanent dipole moment.
- When it comes to an individual hydrogen molecule (not bonding between molecules), the strong force is the covalent bond holding the two hydrogen atoms together.
- Ionic bonds are the strongest intramolecular forces and occur between atoms that transfer electrons, forming cations and anions that attract each other due to opposite charges.
When considering these specific substances given as examples, hydrogen fluoride (HF) will exhibit hydrogen bonding, while hydrochloric acid (HCl) will have dipole-dipole forces as the most significant intermolecular forces. Propane (C3H8), being a nonpolar molecule, will primarily exhibit London dispersion forces. Methanol (CH3OH), due to its OH group, can form hydrogen bonds. Hydrogen sulfide (H2S), though less electronegative than oxygen, will also have dipole-dipole interactions due to the polarity induced by the differing electronegativities of hydrogen and sulfur.