Question

Place the following substances in order of decreasing boiling point.

N2 O2 H2
A) O2 > H2 > N2
B) N2 > H2 > O2
C) N2 > O2 > H2
D) O2 > N2 > H2
E) H2 > N2 > O2

Answer 1

The substances N2, O2, and H2 should be arranged in decreasing order of boiling point based on their size and intermolecular forces, which are London dispersion forces for these nonpolar molecules. The correct order is N2 > O2 > H2.

Step-by-step explanation:

To arrange the substances N2, O2, and H2 in order of decreasing boiling point, you need to consider their intermolecular forces. The boiling point is influenced by the type of intermolecular forces present among molecules. In these three diatomic molecules, only London dispersion forces are present because all are nonpolar. Generally, the boiling point increases with the size and mass of the molecules, as larger molecules have more electrons which lead to stronger dispersion forces.

Therefore, the correct order is N2 > O2 > H2. Nitrogen (N2) has the highest boiling point because it is the largest molecule with more mass compared to oxygen (O2) and hydrogen (H2). Oxygen has a slightly lower boiling point than nitrogen, while hydrogen, being the smallest and lightest, has the lowest boiling point among the three. So the correct option is C) N2 > O2 > H2.