Grade 12 chemistry
Which one of the following exhibits dipole-dipole attraction between molecules?
Question 18 options:
a) AsH3
b) Br2
c) PI3
d) BCl3
e) NO2
is the answer a) or e)?
The answer is e) NO2. NO2 exhibits dipole-dipole attraction between molecules because it has a polar covalent bond due to the difference in electronegativity between nitrogen and oxygen. This results in a partial positive charge on nitrogen and a partial negative charge on oxygen, creating a dipole moment. Dipole-dipole interactions occur when the positive end of one molecule attracts the negative end of another molecule.
The answer is e) NO2. NO2 exhibits dipole-dipole attraction between molecules because it has a polar covalent bond due to the difference in electronegativity between nitrogen and oxygen atoms.
To determine which one of the given options exhibits dipole-dipole attraction between molecules, we need to analyze the molecular geometry and the presence of polar bonds in each molecule.
a) AsH3 (arsine): This molecule has a trigonal pyramidal geometry and contains polar bonds between the As and H atoms. Due to the asymmetrical shape and the polar bonds, AsH3 exhibits dipole-dipole attraction.
b) Br2 (dibromine): This molecule consists of two bromine atoms, which have an identical electronegativity. Since there is no difference in electronegativity between the atoms, Br2 does not exhibit dipole-dipole attraction. It only displays London dispersion forces.
c) PI3 (phosphorus triiodide): PI3 has a pyramidal geometry and contains polar bonds between the P and I atoms. Similar to AsH3, the asymmetrical shape and the presence of polar bonds allow PI3 to exhibit dipole-dipole attraction.
d) BCl3 (boron trichloride): BCl3 has a trigonal planar geometry but does not contain polar bonds since boron and chlorine have similar electronegativities. Therefore, BCl3 does not exhibit dipole-dipole attraction.
e) NO2 (nitrogen dioxide): NO2 has a bent (V-shaped) geometry and contains polar bonds between the N and O atoms. The asymmetrical shape and polar bonds make NO2 exhibit dipole-dipole attraction.
From the options given, both a) AsH3 and e) NO2 exhibit dipole-dipole attraction between molecules.