Final answer:
Option B is true; hydrogen bonds are weaker than covalent bonds. They result from an electrostatic attraction between a hydrogen atom bonded to a highly electronegative atom and a neighboring molecule's electronegative atom, most commonly oxygen or nitrogen.
Step-by-step explanation:
In addressing the question, which statement is true regarding hydrogen bonds:
B. Hydrogen bonds are weaker than covalent bonds.
Firstly, let's clarify what hydrogen bonds are. A hydrogen bond is an intermolecular attractive force in which a hydrogen atom that is covalently bonded to a small, highly electronegative atom (usually oxygen or nitrogen) is attracted to a lone pair of electrons on an atom in a neighboring molecule. This type of bond is considerably weaker than covalent bonds. Covalent bonds involve the sharing of electrons between atoms, forming strong connections within molecules like hydrogen in H2 or carbon and hydrogen in CH4. However, hydrogen bonds are not a sharing of electrons but rather a weak electrostatic attraction between polar molecules or different parts of the same molecule where hydrogen is involved.
Regarding the other options, A is incorrect since hydrogen bonds do not involve the sharing of electrons but rather the attraction between the dipole moments of polar molecules. C is incorrect because hydrogen bonds typically occur in polar molecules, not non-polar molecules. D is incorrect because while hydrogen bonds do contribute to the structure of double-stranded DNA, they do not provide rigidity but rather flexibility allowing the DNA to unzip for replication and protein synthesis.