Which of the following exhibits dipole-dipole forces as its strongest intermolecular force?
Question 1 options:
a) NH3
b) CH4
c) BCl3
d) CO2
e) H2
a) NH3
To determine which of the following substances exhibits dipole-dipole forces as its strongest intermolecular force, let's analyze the molecular structures of each option.
a) NH3 (ammonia): In ammonia, the nitrogen atom is more electronegative than the hydrogen atoms, resulting in a polar molecule with a dipole moment. The partial positive charge on the hydrogen atoms and the partial negative charge on the nitrogen atom allow for dipole-dipole interaction.
b) CH4 (methane): Methane is a nonpolar molecule. Carbon and hydrogen have similar electronegativities, resulting in a symmetrically distributed electron density. Hence, CH4 does not exhibit dipole-dipole forces.
c) BCl3 (boron trichloride): BCl3 is also a nonpolar molecule. The boron atom is less electronegative than chlorine, but the molecule lacks a dipole moment due to its trigonal planar geometry, where the chlorine atoms are symmetrically arranged around the central boron atom. Therefore, BCl3 does not exhibit dipole-dipole forces.
d) CO2 (carbon dioxide): Carbon dioxide is a linear molecule with a carbon-oxygen double bond. The electronegativity difference between carbon and oxygen is relatively small, resulting in a nonpolar molecule. CO2 does not exhibit dipole-dipole forces.
e) H2 (hydrogen gas): Hydrogen gas is composed of diatomic molecules, and each hydrogen atom has the same electronegativity. Therefore, H2 is a nonpolar molecule, and it does not exhibit dipole-dipole forces.
From the options given, only NH3 (ammonia) exhibits dipole-dipole forces as its strongest intermolecular force.