1) The order of the boiling points for the hydrogen halides, except for HF, is

HI > HBr > HCl. The reason for this order can be attributed to

a) the relative covalent bond strengths.
b) differences in hydrogen bonding.
c) differences in dipole-dipole attractions.
d) differences in London forces.
e) differences in dipole/induced dipole interactions

I chose answer e, dipole/induced dipole interactions. Is this correct?

Every book I've read attributes the rise in boiling points from HCl to HI as due to increased molar mass; this site attributes it to increased London forces due to the larger number of electrons.

http://en.wikipedia.org/wiki/Hydrogen_halide

To determine the correct answer to this question, we need to consider the factors that influence the boiling points of the hydrogen halides (HI, HBr, HCl, and HF).

First, let's discuss each of the options and evaluate their relevance to the boiling point order:

a) Relative covalent bond strengths: This factor refers to the strength of the bond between hydrogen and the halogen atom. In this case, hydrogen halides have relatively similar covalent bond strengths, so this factor alone does not explain the boiling point order.

b) Differences in hydrogen bonding: Hydrogen bonding occurs when hydrogen is directly bonded to a highly electronegative atom, such as fluorine, oxygen, or nitrogen. This type of bonding is stronger than dipole-dipole interactions and London forces. However, since the question stated "except for HF," we can exclude hydrogen bonding as the main reason for the boiling point order.

c) Differences in dipole-dipole attractions: Dipole-dipole interactions occur when polar molecules have attractive forces between their positive and negative ends. Since dipole-dipole interactions increase with increasing polarity, this factor can contribute to the boiling point order of the hydrogen halides.

d) Differences in London forces: London forces, also known as dispersion forces, occur in all molecules and are caused by temporary fluctuations in electron distribution, resulting in temporary dipoles. These forces increase with the size of the molecules and can contribute to boiling points. However, they are less significant compared to dipole-dipole interactions in this case.

e) Differences in dipole/induced dipole interactions: Dipole/induced dipole interactions occur when a polar molecule induces a temporary dipole in a neighboring nonpolar molecule. This can influence the boiling point, especially when the molecular polarity is significant. While dipole/induced dipole interactions can play a role, they are not the primary factor determining the boiling point order in this case.

Considering all of the above, the correct answer is c) differences in dipole-dipole attractions. Dipole-dipole interactions increase with increasing polarity, and since the order of boiling points for the hydrogen halides correlates with their electronegativity differences (HF being more electronegative than the rest), it suggests that dipole-dipole attractions are the main reason for the observed boiling point order.