Which of the following diatomic molecules is the most polar:
1. Br2
2. HCl
3. H2
4. HBr
Correct Answer: 2.
Comments to the instructor: Br2 and H2 are nonpolar molecules; the electronegativity
difference between H and Cl is greater than the electronegativity difference between H
and Br.
Which of the following molecules is nonpolar:
1. CH3Cl
2. CO
3. H2O
4. CH4
Correct Answer: 4.
Comments to the instructor: Have students draw Lewis structures, first. The symmetry
of CH4 makes it the only nonpolar molecule among the choices given.
Of the following species: NF3, BF3, CO2, CH3OH, which pair
is polar:
1. NF3, BF3
2. BF3, CO2
3. NF3, CH3OH
4. CO2, CH3OH
