Final answer:
H2O (water) is the molecule that can participate in dipole-dipole interactions due to its polar nature and significant molecular dipole, allowing for strong intermolecular forces.
Step-by-step explanation:
The student asked which among C2H6, CO2, H2O, and H2 will participate in dipole-dipole interactions. Molecules engage in dipole-dipole interactions when they have permanent dipole moments, which occurs when there is an uneven distribution of electron density across the molecule.
Specifically, H2O (water) is the molecule from the list that can exhibit dipole-dipole interactions due to its polar nature. Water molecules are polar because the OH bond moments do not cancel out, and it has a significant molecular dipole, which allows strong interactions between its molecules.
On the other hand, C2H6 (ethane) is nonpolar, as is H2 (hydrogen), so neither exhibit dipole-dipole interactions. Although CO2 has polar CO bonds, the molecule is linear and symmetrical, meaning that these dipoles cancel out, rendering the overall molecule nonpolar and incapable of dipole-dipole interactions.