Which one of the following should have the lowest boiling point?
Question 4 options:
a) HBr
b) Zn
c) N2
d) CH3OH
e) NO
c) N2
To determine which substance should have the lowest boiling point among the given options, we can look at their molecular structures and intermolecular forces.
Option a) HBr is a polar molecule with hydrogen bonding potential, which results in relatively strong intermolecular forces.
Option b) Zn is a metal, and metals generally have high boiling points due to their metallic bonding.
Option c) N2 is a diatomic non-polar molecule with London dispersion forces being the primary intermolecular force.
Option d) CH3OH is a polar molecule with hydrogen bonding potential.
Option e) NO is a diatomic polar molecule with a partial positive and partial negative charge on the Nitrogen and Oxygen atom, respectively.
Based on the intermolecular forces involved, we can rank the substances from lowest to highest boiling point as follows:
c) N2 < e) NO < a) HBr < d) CH3OH < b) Zn
Therefore, the substance with the lowest boiling point among the given options should be N2 (option c).
To determine which one of the given options should have the lowest boiling point, we need to consider the factors that affect boiling point.
Boiling point is typically influenced by the strength of intermolecular forces between molecules. The stronger the intermolecular forces, the higher the boiling point. There are several types of intermolecular forces, including London dispersion forces, dipole-dipole forces, and hydrogen bonding.
Let's evaluate each option:
a) HBr: HBr is a polar molecule and it exhibits dipole-dipole forces. It also has London dispersion forces. However, it is worth noting that hydrogen bonding does not occur between HBr molecules. As a result, HBr has moderate intermolecular forces.
b) Zn: Zinc (Zn) is a metal and does not form discrete molecules. Since it does not have intermolecular forces, it does not have a boiling point.
c) N2: Nitrogen (N2) is a nonpolar molecule and it only exhibits London dispersion forces. Nitrogen has relatively weak intermolecular forces compared to polar molecules.
d) CH3OH: Methanol (CH3OH) is a polar molecule that exhibits dipole-dipole forces as well as hydrogen bonding. Hydrogen bonding is a strong intermolecular force, so methanol has higher intermolecular forces compared to the other options.
e) NO: Nitric oxide (NO) is a radical molecule that does not exhibit dipole-dipole forces or hydrogen bonding. It only has London dispersion forces, which are weaker than hydrogen bonding.
Based on the analysis above, we can conclude that option b) Zn does not have a boiling point since it is a metal. Among the remaining options, option c) N2 should have the lowest boiling point because it only exhibits weak London dispersion forces.
Therefore, option c) N2 should have the lowest boiling point.